以防万一，更新一个最简单的 //获取用户设备信息，屏幕宽度 tt.getSystemInfo({ success: res => { console.log(res, 'getSystemInfo') that.setData({ screenWidth: res.screenWidth, screenHeight: res.screenHeight, pixelRatio: res.pixelRatio, }) console.log(that.data.pixelRatio, that.data.screenWidth, that.data.screenHeight) } }) // 创建canvas wx.canvasToTempFilePath({ canvasId: 'canvasId', // canvasId width: that.data.screenWidth, // 输出canvas画布的宽 height: that.data.screenHeight, // 输出canvas画布的高 destWidth: that.data.screenWidth * that.data.pixelRatio, // 输出canvas画布的宽 * 设备像素比 destHeight: that.data.screenHeight * that.data.pixelRatio, // 输出canvas画布的高 * 设备像素比 success: (res) => { console.log(res) }, fail: (err) => { console.log(err) } })