废话不多说，先上一张效果图！

建立两个canvas标签，先绘制底层的浅灰色圆圈背景，再绘制上层的红色进度条。

                      开始动态绘制  

特别注意：底层的canvas最好使用
z-index:-5；放置于底层

page {  width: 100%;  height: 100%;  background-color: #fff;}.circle-box {  text-align: center;  margin-top: 10vw;}.circle {  position: absolute;  left: 0;  right: 0;  margin: auto;}.draw_btn {  width: 35vw;  position: absolute;  top: 33vw;  right: 0;  left: 0;  margin: auto;  border: 1px #000 solid;  border-radius: 5vw;}

//获取应用实例var app = getApp()var interval;var varName;var ctx = wx.createCanvasContext('canvasArcCir');Page({  data: {  },  drawCircle: function () {    clearInterval(varName);    function drawArc(s, e) {      ctx.setFillStyle('white');      ctx.clearRect(0, 0, 200, 200);      ctx.draw();      var x = 100, y = 100, radius = 96;      ctx.setLineWidth(5);      ctx.setStrokeStyle('#d81e06');      ctx.setLineCap('round');      ctx.beginPath();      ctx.arc(x, y, radius, s, e, false);      ctx.stroke()      ctx.draw()    }    var step = 1, startAngle = 1.5 * Math.PI, endAngle = 0;    var animation_interval = 1000, n = 60;    var animation = function () {      if (step <= n) {        endAngle = step * 2 * Math.PI / n + 1.5 * Math.PI;        drawArc(startAngle, endAngle);        step++;      } else {        clearInterval(varName);      }    };    varName = setInterval(animation, animation_interval);  },  onReady: function () {    //创建并返回绘图上下文context对象。    var cxt_arc = wx.createCanvasContext('canvasCircle');    cxt_arc.setLineWidth(6);    cxt_arc.setStrokeStyle('#eaeaea');    cxt_arc.setLineCap('round');    cxt_arc.beginPath();    cxt_arc.arc(100, 100, 96, 0, 2 * Math.PI, false);    cxt_arc.stroke();    cxt_arc.draw();  },  onLoad: function (options) {  }})

1、关于小程序canvas绘制，请观看微信小程序官方文档绘制