Cladding mode coupling will lead loss on the shoft wavelength side of Bragg wavelength and thus limits the grating’s wide use. A novel photosensitive fiber design is proposed that have both the depressed cladding and the photosensitive inner cladding in the same fiber. It can suppress cladding mode coupling in some extent. B/Ge co coped fiber grating with depressed cladding also doped with boron and gemania was fabricated. The transmission spectrum of written grating in it verified its larger photosensitivity and suppression of cladding mode coupling.