看下效果吧：

---直接上代码喽---

1、template部分

<div class="box">
    <div class="butt" @click="buttClick">
       <div>哈哈哈</div>
    </div>
 </div>

2、css部分

.box {
    width: 500px;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #000;
    .butt {
        display: flex;
        align-items: center;
        justify-content: center;
        position: relative;
        width: 150px;
        height: 50px;
        border: 1px solid transparent;
        color: #000;
        overflow: hidden;
        box-sizing: content-box;
        z-index: 0;
        cursor: pointer;
        border-radius: 25px;
        box-shadow: inset 0 0 6px 2px #888;
        div {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 144px;
            height: 44px;
            color: #000;
            border-radius: 23px;
            background-color: #fff;
        }
        &::before {
            position: absolute;
            content: "";
            top: 50%;
            left: 50%;
            width: 30px;
            height: 150px;
            animation: sss 6s linear infinite;
            z-index: -1;
            transform-origin: center;
            transform: translate(-50%, -50%);
            background-image: linear-gradient(to left, #e71919, #d849b1, #f7f31d);
        }
    }
}

@keyframes sss {
    100% {
        transform: translate(-50%, -50%) rotate(720deg);
    }
}