I've attach a picture of the pulley I'm using hope that can be help
thank you

Well all you need to do is measure the OD of the 2 pulleys then divide but that probably will not work well for accurate motion control.

What exactly are you building ?

I'm building cnc router for woodworking and I did try to use timing pulley but it is not available in my town I'm form Egypt so if it important I may make an order  by any on line store. sorry for my poor writing

Your writing is really quite good.
I'm sure you would have been dissapointed if you had used the smooth pulleys.
Good luck to you and post some pictures of your machine when you get it together.
Regards,
RC