Did you assign the model to a bone? If you didn't, the towel will naturally not move as nothing is telling it to.

well do "link" is the same as "assign"? cuz i did link the bone with the towel
but if not how do i do?

Open your .smd with Notepad ++ and go to Line 3. It should say something along the lines of

0 "bone name" -1

ya i did that, but in game the model stay fix to the charcacter, but when he move, like put is hand up, the hand go trough the towel...the towel dont move with the hand
do you know what i mean?

If you want it to move with the character, you need to rig to more bones. TF2 doesn't simulate cloth physics.

Just to clarify, do you mean that when you, say, walk away, the towel doesn't move, or do you mean that the model clips through the towel?

yeah the model clips through the towel

And thanks pogo ill try the "rig"

okk i tried to skin the bone to the model but when i move the bone...the towel dont move smoothly, its only stretch and it look really bad

I want that when the character move to the left, the towel go the other side because of the winds, like a real towel! and also that the towel colide to the character so that it dont glips trough it!

a towel moving smooth like that but in game and on the character!
http://www.youtube.com/watch?v=qRltpf_Hkn8

TF2 doesn't have cloth physics. Try to make do with character animations and jigglebones

how do i import the animation? the animaiton is only in dmx files and there is no .dmx importer!