The principle of equal-phase shifted fiber Bragg grating is that by introducing a spatial shift at certain position of sampling fiber Bragg grating, equivalent phase shift can be achieved in different frequency channel after Fourier transformation. Firstly, the fiber Bragg grating Turan transmission matrix is used to perform number simulation, and all kinds of phase shifted fiber Bragg grating’s properties are verified in equal-phase shifted fiber Bragg grating. Secondly, according to the report that -2 grade fiber Bragg grating has low reflectivity and equal-phase shifted state can’t be realized, a method for realizing -2 grade equal-phase shifting is proposed and relative verification is performed. Finally, the relationship curve of equal-phase shifted fiber Bragg grating reflectivity changing with length is given.