~~~ .parent{ width: 100%; height: 300px; background: #00f; display: -webkit-box; display: -webkit-flex; justify-content: center;/*水平居中*/ align-items: center;/*垂直居中*/ } .child{ width: 100px; height: 100px; background: white; } <div class="parent"> <div class="child"></div> </div> ~~~