SOURCE

function toCanvas(id ,progress){
                //canvas进度条
                var canvas = document.getElementById(id),
                ctx = canvas.getContext("2d"),
                percent = progress, // 最终百分比
                circleX = canvas.width / 2, // 中心x坐标
                circleY = canvas.height / 2, // 中心y坐标
                radius = 100,// 圆环半径
                lineWidth = 5,  //圆形线条的宽度
                fontSize = 20; //字体大小
                 //两端圆点
                function smallcircle1(cx, cy, r) {
                    ctx.beginPath();
                    //ctx.moveTo(cx + r, cy);
                    ctx.lineWidth = 1;
                    ctx.fillStyle = '#06a8f3';
                    ctx.arc(cx, cy, r,0,Math.PI*2);
                    ctx.fill();
                }
                 function smallcircle2(cx, cy, r) {
                     ctx.beginPath();
                     //ctx.moveTo(cx + r, cy);
                     ctx.lineWidth = 1;
                     ctx.fillStyle = '#00f8bb';
                     ctx.arc(cx, cy, r,0,Math.PI*2);
                     ctx.fill();
                 }

                 //画圆
                 function circle(cx, cy, r) {
                     ctx.beginPath();
                     //ctx.moveTo(cx + r, cy);
                     ctx.lineWidth = lineWidth;
                     ctx.strokeStyle = '#eee';
                     ctx.arc(cx, cy, r, Math.PI*2/3, Math.PI * 1/3);
                     ctx.stroke();
                 }

                // 画弧线
                 function sector(cx, cy, r, startAngle, endAngle, anti) {
                     ctx.beginPath();
                     //ctx.moveTo(cx, cy + r); // 从圆形底部开始画
                     ctx.lineWidth = lineWidth;

                     // 渐变色 - 可自定义
                     var linGrad = ctx.createLinearGradient(
                         circleX-radius-lineWidth, circleY, circleX+radius+lineWidth, circleY
                     );
                     linGrad.addColorStop(0.0, '#06a8f3');
                     linGrad.addColorStop(0.5, '#9bc4eb');
                     linGrad.addColorStop(1.0, '#00f8bb');
                     ctx.strokeStyle = linGrad;

                      //圆弧两端的样式
                     ctx.lineCap = 'round';

                     //圆弧
                     ctx.arc(
                         cx, cy, r,
                         (Math.PI*2/3),
                         (Math.PI*2/3) + endAngle/100 * (Math.PI*5/3),
                         false
                     );
                     ctx.stroke();
                 }

                  //刷新
                 function loading() {
                     if (process >= percent) {
                         clearInterval(circleLoading);
                     }

                      //清除canvas内容
                     ctx.clearRect(0, 0, circleX * 2, circleY * 2);

                    //中间的字
                     ctx.font = fontSize + 'px April';
                     ctx.textAlign = 'center';
                     ctx.textBaseline = 'middle';
                     ctx.fillStyle = '#999';
                     ctx.fillText(parseFloat(process).toFixed(0) + '%', circleX, circleY);    
                  
                     //圆形
                     circle(circleX, circleY, radius);
                     
                      //圆弧
                     sector(circleX, circleY, radius, Math.PI*2/3, process);
                    // 两端圆点
                     smallcircle1(150+Math.cos(2*Math.PI/360*120)*100, 150+Math.sin(2*Math.PI/360*120)*100, 5);
                     smallcircle2(150+Math.cos(2*Math.PI/360*(120+process*3))*100, 150+Math.sin(2*Math.PI/360*(120+process*3))*100, 5);
                     //控制结束时动画的速度
                     if (process / percent > 0.90) {
                         process += 0.30;
                     } else if (process / percent > 0.80) {
                         process += 0.55;
                     } else if (process / percent > 0.70) {
                         process += 0.75;
                     } else {
                         process += 1.0;
                     }
                 }

                 var process = 0.0;  //进度
                 var circleLoading = window.setInterval(function () {
                     loading();
                 }, 20);
                     
            }
//第二部分，调用封装好的代码：
            toCanvas('can',100);

<canvas id="can" width='300px' height="300px"></canvas>