html

<div class="loop-pie">
    <div class="loop-pie-line loop-pie-r">
        <div class="loop-pie-c loop-pie-rm" id="loop-rc"></div>
    </div>
    <div class="loop-pie-line loop-pie-l">
        <div class="loop-pie-c loop-pie-lm" id="loop-lc"></div>
    </div>

</div>

css

 * {
        margin:0px;
        padding:0px;
    }
    .loop-pie {
        position:relative;
        width:200px;
        height:200px;
        margin:60px;
    }
    .loop-pie-line {
        position:absolute;
        width:50%;
        height:100%;
        top:0;
        overflow:hidden;
    }
    .loop-pie-l {
        top:0px;
        left:0px;
    }
    .loop-pie-r {
        top:0px;
        -webkit-transform:rotate(180deg);
        right:0px
    }
    .loop-pie-c {
        width:200%;
        height:100%;
        border:4px solid transparent;
        border-radius:50%;
        position:absolute;
        box-sizing:border-box;
        top:0;
        -webkit-transform:rotate(-45deg);
    }
    .loop-pie-rm {
        border-top:4px solid #baedee;
        border-left:4px solid #baedee;
        border-bottom:4px solid #1ac4c7;
        border-right:4px solid #1ac4c7;
    }
    .loop-pie-lm {
        border-top:4px solid #baedee;
        border-left:4px solid #baedee;
        border-bottom:4px solid #1ac4c7;
        border-right:4px solid #1ac4c7;
    }

js

 //假如当前进度为40%
    loadPercent(10, 100);

    function loadPercent(x, y) {
        var rotate = (x / y) * 360
        var rotateRight = 0
        var rotateLeft = 0
        if (rotate < 180) {
            rotateRight = rotate + (-45)
        } else {
            rotateRight = 135
            rotateLeft = (rotate - 180 - 45)
            $("#loop-lc").css({
                "-webkit-transform": "rotate(" + rotateLeft + "deg)",
            })
        }

        $("#loop-rc").css({
            "-webkit-transform": "rotate(" + rotateRight + "deg)",
        })


    }