i got mods for morrowind 3 but there for the pc will thay work on my xbox

Some will, some won't - mostly depending on the memory usage of the mods (I believe), as the XBox's memory is so limited (it's 64MB, and that includes video memory). Have a look through the FAQs on this page to see what you can and can't do, and have a look at RWolf's mod pack when it comes out (see the post entitled "W00h00!" for details).

Try the "Converting Pc Mods To The Xbox" sticky post at the top of the forum it may help