Abstract: A new synthetic strategy for fiber grating was proposed. For a given reflection spectrum of a fiber Bragg grating, the index profile of fiber Bragg grating could be calculated by a layer peeling algorithm. Some superimposed fiber grating with different apodisation functions were used to fit this index profile. The special reflection spectrum of a fiber Bragg grating could be realized by controlling the superimposed fiber grating's parameters adjustment.The relative error between the reflection spectrum of synthetic superimposed fiber grating and the goal spectrum is less than 4.0%. It is a sample and quick method for fiber grating synthesis problems which is easy to implement.