您是否尝试添加“方向”,如：

@media only screen 
and (min-device-width : 480px) 
and (max-device-width : 800px) 
and (orientation : landscape) {

}

@media only screen 
and (min-device-width : 480px) 
and (max-device-width : 800px) 
and (orientation : portrait) {

}