<link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css">  
        <script src="https://cdn.staticfile.org/jquery/2.1.1/jquery.min.js"></script>
        <script src="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>

position: absolute;top: 50%;left: 50%;right: 0;bottom: 0;transform: translate(-50%,-50%);

.container{
                display:table;
                height:100%;
            }
.row{
                display: table-cell;
                vertical-align: middle;
            }

<div class="container">
    <div class="row row-centered">
        內容
    </div>
</div>