看看这个，也许这会有帮助。

<div class="video-responsive"><iframe src="https://www.youtube-nocookie.com/embed/1Cz2Xzm6knM/videoseries?list=PLq-1Cz2Xzm6knM-1Cz2Xzm6knM&amp;rel=0" width="420" height="315" frameborder="0" allowfullscreen="allowfullscreen"></iframe></div>


.video-responsive{
    overflow:hidden;
    padding-bottom:56.25%;
    position:relative;
    height:0;
}
.video-responsive iframe{
    left:0;
    top:0;
    height:100%;
    width:100%;
    position:absolute;
}