A fabrication method of multi-wavelength fiber Bragg grating (FBG) is intr oduced in this paper.Using the scan exposure method,multi-wavelength FBG can be successfully manufactured thr ough applying different tensile forces during multiple exposures on the same fiber.Experiment results sh ow that the position and the overlap of different sub FBGs will greatly affect the spectrum of every sub-FBG .The spectrum of each sub-FBG will be affected by short wave oscillation unless the lengths and positions of a ll sub-FBGs are fully overlapped.For hydrogen loaded fiber,the wavelength and reflectivity of the nth level FBG will increase as the (n+1)th level FBG is written.But for germanium doped photosensitive fiber,multiple exposures wil l increase the wavelength of previous sub-FBGs while decrease the reflectivity of all sub-FBGs.Through well distributing exposure intensity of every sub-FBG,a four-wavelength FBG with the same sub FBG′s spectrum is fabri cated on a hydrogen loaded single mode fiber,and every sub-FBG has the same wavelength temperature and t ens ile coefficient.