select {
border: 0;
display: block;
position: relative;
min-height: 1.146667rem;
line-height: 1.146667rem;
white-space: nowrap;
width: 100%;
overflow: hidden;
padding-right: .6rem;
background-color: #eee;
background: transparent;
appearance:none;
-moz-appearance:none; /* Firefox */
-webkit-appearance:none; /* Safari 和 Chrome */
}

去掉邊框：border: 0; background: transparent;

去掉小三角：

appearance:none;
-moz-appearance:none; /* Firefox */
-webkit-appearance:none; /* Safari 和 Chrome */