.position_Box {
    position: relative;
    width: 600px;
    height: 360px;
    margin: 0 auto;
    border: 0;
    left: 0;
    top: 0;
    background-color: #ffffff;
    text-align: center;
}
 
.position_Box .center_img {
     position: absolute;
     top: 0;
     left: 0;
     right: 0;
     bottom: 0;
     margin: auto;
     width:320px;
     height:230px;
}