設定flash的object的wmode為transparent就好了：
<OBJECT
codeBase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=7,0,19,0" classid=clsid:D27CDB6E-AE6D-11cf-96B8-444553540000 width=536 height=260>
<PARAM NAME="wmode" VALUE="transparent">
<PARAM NAME="Movie" VALUE="flash路徑">
<embed src="flash路 徑" quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash" width="536" height="260" wmode="transparent"></embed></OBJECT>
![As3 , Flash 序列化[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)