diff --git a/examples/marks.js b/examples/marks.js
index a487bc0..6e1dac6 100644
--- a/examples/marks.js
+++ b/examples/marks.js
@@ -7,7 +7,15 @@ var ReactDOM = require('react-dom');
 var Slider = require('rc-slider');
 
 var style = {width: 400, margin: 50};
-var marks = ['A','B','C','D', 'E', 'F'];
+var marks = {
+  0: 'A',
+  20: 'B',
+  40: 'C',
+  60: 'D',
+  80: 'E',
+  100: 'F'
+};
+
 var log = function(value) {
   console.log(value);
 };
diff --git a/src/Marks.jsx b/src/Marks.jsx
index 7a03023..db7ace7 100644
--- a/src/Marks.jsx
+++ b/src/Marks.jsx
@@ -1,35 +1,36 @@
 import React from 'react';
 import rcUtil from 'rc-util';
 
-const Marks = ({className, marks, index, included}) => {
-  const marksLen = marks.length;
-  const unit = 100 / (marksLen - 1);
+const Marks = ({className, marks, included, upperBound, lowerBound, max, min}) => {
+  const marksKeys = Object.keys(marks);
+  const marksCount = marksKeys.length;
+  const unit = 100 / (marksCount - 1);
   const markWidth = unit / 2 + '%';
 
-  const elements = [];
-  for (let i = 0; i < marksLen; i++) {
-    const isActived = (included && i <= index) || (!included && i === index);
+  const range = max - min;
+  const elements = marksKeys.map(parseFloat).map((point) => {
+    const isActived = (!included && point === upperBound) ||
+            (included && point <= upperBound && point >= lowerBound);
     const markClassName = rcUtil.classSet({
       [className + '-text']: true,
       [className + '-text-active']: isActived,
     });
 
     const style = { width: markWidth };
-    const offset = unit * i;
-    if (i === marksLen - 1) {
+    if (point === marksCount - 1) {
       style.right = -unit / 4 + '%';
+    } else if (point === 0) {
+      style.left = -unit / 4 + '%';
     } else {
-      style.left = (i > 0 ? offset - unit / 4 : -unit / 4) + '%';
+      style.left = (point - min) / range * 100 - unit / 4 + '%';
     }
 
-    elements.push(<span className={markClassName} style={style} key={i}>
-                    {marks[i]}
-                  </span>);
-  }
+    return (<span className={markClassName} style={style} key={point}>
+             {marks[point]}
+            </span>);
+  });
 
-  return (<div className={className}>
-            {elements}
-          </div>);
+  return <div className={className}>{elements}</div>;
 };
 
 export default Marks;
diff --git a/src/Slider.jsx b/src/Slider.jsx
index 2baca4a..99fe49a 100644
--- a/src/Slider.jsx
+++ b/src/Slider.jsx
@@ -25,6 +25,10 @@ function pauseEvent(e) {
   e.preventDefault();
 }
 
+function isEmpty(collection) {
+  return Object.keys(collection).length === 0;
+}
+
 // This is an utility method, tries to get property, then defaultPropery with
 // special check using 'in', because propery can be '0'
 function propOrDefault(props, name, fallback) {
@@ -40,7 +44,7 @@ class Slider extends React.Component {
     let upperBound;
     let lowerBound;
     const initialValue = props.range ? [0, 0] : 0;
-    if (props.marks.length > 0) {
+    if (!isEmpty(props.marks)) {
       const index = propOrDefault(props, 'index', initialValue);
       ({lowerBound, upperBound} = this.getBoundsFromIndex(index, props));
     } else {
@@ -139,7 +143,7 @@ class Slider extends React.Component {
     pauseEvent(e);
   }
 
-  onSliderMouseDown(e) {
+  onMouseDown(e) {
     const position = getMousePosition(e);
     this.onStart(position);
     this.addDocumentEvents('mouse');
@@ -209,10 +213,10 @@ class Slider extends React.Component {
   getIndex(value) {
     const {marks, min, max, step} = this.props;
 
-    if (marks.length === 0) {
+    if (isEmpty(marks)) {
       return Math.floor((value - min) / step);
     }
-    const unit = ((max - min) / (marks.length - 1)).toFixed(5);
+    const unit = ((max - min) / (Object.keys(marks).length - 1)).toFixed(5);
     return Math.round(value / unit);
   }
 
@@ -228,6 +232,17 @@ class Slider extends React.Component {
     };
   }
 
+  getPoints() {
+    const {marks, step, dots, min, max} = this.props;
+    const points = new Set(Object.keys(marks));
+    if (step > 1 && dots) {
+      for (let i = min; i <= max; i = i + step) {
+        points.add(i);
+      }
+    }
+    return Array.from(points);
+  }
+
   getSliderLength() {
     const slider = this.refs.slider;
     if (!slider) {
@@ -249,7 +264,7 @@ class Slider extends React.Component {
     const {handle, lowerBound, upperBound} = state;
     const props = this.props;
     const {marks, min, max} = props;
-    const marksLen = marks.length;
+    const marksLen = Object.keys(marks).length;
     const step = (marksLen > 0) ? (max - min) / (marksLen - 1) : props.step;
 
     let val = v;
@@ -295,7 +310,7 @@ class Slider extends React.Component {
   }
 
   calcValueFromIndex(index, props) {
-    const marksLen = props.marks.length;
+    const marksLen = Object.keys(props.marks).length;
     if (marksLen > 0) {
       const value = ((props.max - props.min) / (marksLen - 1)) * (index);
       return parseFloat(value.toFixed(5));
@@ -305,7 +320,7 @@ class Slider extends React.Component {
 
   triggerEvents(event, v) {
     const props = this.props;
-    const hasMarks = (props.marks.length > 0);
+    const hasMarks = !isEmpty(props.marks);
     if (props[event]) {
       let data;
       if (hasMarks) {
@@ -352,9 +367,9 @@ class Slider extends React.Component {
 
   render() {
     const {handle, upperBound, lowerBound} = this.state;
-    const {className, prefixCls, disabled, included, dots, range,
-           marks, step, max, min, tipTransitionName, tipFormatter, children} = this.props;
-    const marksLen = marks.length;
+    const {className, prefixCls, disabled, included, range,
+           marks, max, min, tipTransitionName, tipFormatter, children} = this.props;
+    const marksLen = Object.keys(marks).length;
 
     const sliderClassName = classSet({
       [prefixCls]: true,
@@ -382,33 +397,20 @@ class Slider extends React.Component {
                  offset={lowerOffset} value={lowerBound} dragging={handle === 'lowerBound'} />);
     }
 
-    const upperIndex = this.getIndex(upperBound);
-
-    let steps = null;
-    if (marksLen > 0 || (step > 1 && dots)) {
-      const stepsClassName = prefixCls + '-step';
-      const stepNum = marksLen > 0 ? marksLen : Math.floor((max - min) / step) + 1;
-      steps = (<Steps className={stepsClassName} stepNum={stepNum}
-                      lowerIndex={this.getIndex(lowerBound)} upperIndex={upperIndex}
-                      included={included || range}/>);
-    }
-
-    let mark = null;
-    if (marksLen > 0) {
-      const markClassName = prefixCls + '-mark';
-      mark = (<Marks className={markClassName} marks={marks}
-                     index={upperIndex} included={included}/>);
-    }
-
+    const isIncluded = included || range;
     return (
       <div ref="slider" className={sliderClassName}
            onTouchStart={disabled ? noop : this.onTouchStart.bind(this)}
-           onMouseDown={disabled ? noop : this.onSliderMouseDown.bind(this)}>
+           onMouseDown={disabled ? noop : this.onMouseDown.bind(this)}>
         {track}
         {upper}
         {lower}
-        {steps}
-        {mark}
+        <Steps prefixCls={prefixCls} points={this.getPoints()}
+               included={isIncluded} lowerBound={lowerBound}
+               upperBound={upperBound} max={max} min={min} />
+        <Marks className={prefixCls + '-mark'} marks={marks}
+               included={isIncluded} lowerBound={lowerBound}
+               upperBound={upperBound} max={max} min={min} />
         {children}
       </div>
     );
@@ -435,7 +437,7 @@ Slider.propTypes = {
     React.PropTypes.number,
     React.PropTypes.arrayOf(React.PropTypes.number),
   ]),
-  marks: React.PropTypes.array,
+  marks: React.PropTypes.object,
   included: React.PropTypes.bool,
   className: React.PropTypes.string,
   prefixCls: React.PropTypes.string,
@@ -455,7 +457,7 @@ Slider.defaultProps = {
   max: 100,
   step: 1,
   defaultIndex: 0,
-  marks: [],
+  marks: {},
   included: true,
   className: '',
   prefixCls: 'rc-slider',
diff --git a/src/Steps.jsx b/src/Steps.jsx
index da2cdb0..816dcd5 100644
--- a/src/Steps.jsx
+++ b/src/Steps.jsx
@@ -1,28 +1,23 @@
 import React from 'react';
-import rcUtil from 'rc-util';
+import { classSet } from 'rc-util';
 
-const Steps = ({className, stepNum, included, lowerIndex, upperIndex}) => {
-  const dotClassName = className.replace('step', 'dot');
-  const unit = 100 / (stepNum - 1);
-
-  const elements = [];
-  for (let i = 0; i < stepNum; i++) {
-    const offset = unit * i + '%';
+const Steps = ({prefixCls, points, included, lowerBound, upperBound, max, min}) => {
+  const range = max - min;
+  const elements = points.map(parseFloat).map((point) => {
+    const offset = (point - min) / range * 100 + '%';
     const style = { left: offset };
 
-    const isActived = (included && i <= upperIndex && i >= lowerIndex ) ||
-            (!included && i === upperIndex);
-    const stepClassName = rcUtil.classSet({
-      [dotClassName]: true,
-      [dotClassName + '-active']: isActived,
+    const isActived = (!included && point === upperBound) ||
+            (included && point <= upperBound && point >= lowerBound);
+    const pointClassName = classSet({
+      [prefixCls + '-dot']: true,
+      [prefixCls + '-dot-active']: isActived,
     });
 
-    elements.push(<span className={stepClassName} style={style} key={i} />);
-  }
+    return <span className={pointClassName} style={style} key={point} />;
+  });
 
-  return (<div className={className}>
-            {elements}
-          </div>);
+  return <div className={prefixCls + '-step'}>{elements}</div>;
 };
 
 export default Steps;