Hi friends.
I have created Dhtml menu(when hover your mouse the menu appear) and put underneath it a flash swf. When you hover your mouse on the menu, the menu disappear under the flash file.

please help me how to solve this problem.

This is a known issue.

Save the SWF file as transparent when you publish it out of Flash.
You may have to also set the menu to position:absolute with z-index greater than the body of the page where the Flash file sits.