一、定位 盒子寬高已知, position: absolute; left: 50%; top: 50%; margin-left:-自身一半寬度; margin-top: -自身一半高度; 二、table-cell佈局 父級 display: table-cell; vertical-align: middle; 子級 margin: 0 auto; 三、定位 + transform ; 適用於 子盒子 寬高不定時; (這裏是本人經常使用方法) position: relative / absolute; /*top和left偏移各爲50%*/ top: 50%; left: 50%; /*translate(-50%,-50%) 偏移自身的寬和高的-50%*/ transform: translate(-50%, -50%); 注意這裏啓動了3D硬件加速哦 會增長耗電量的 (至於何是3D加速 請看瀏覽器進程與線程篇) 四、flex 佈局 父級: /*flex 佈局*/ display: flex; /*實現垂直居中*/ align-items: center; /*實現水平居中*/ justify-content: center; 再加一種水平方向上居中 :margin-left : 50% ; transform: translateX(-50%); <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>Document</title> <style> .box { width: 300px; height: 300px; background: silver; margin: 80px auto; display: flex; flex-direction: column; flex-wrap: nowrap; justify-content: space-between; align-items: center; } .top, .middle, .bottom { width: 100%; display: flex; flex-direction: row; flex-wrap: nowrap; justify-content: space-between; align-items: center; } </style> </head> <body> <div class="box"> <div class="top"> <div class="left">1</div> <div class="center">2</div> <div class="right">3</div> </div> <div class="middle"> <div class="left">4</div> <div class="center">5</div> <div class="right">6</div> </div> <div class="bottom"> <div class="left">7</div> <div class="center">8</div> <div class="right">9</div> </div> </div> </body> </html>