Fiber Bragg grating(FBG) under transverse force to a small grating section was studied by numerical simulation and experimentation.A numerical simulation based on the transfer matrix formulation approach was used to calculate the consequent changes in reflected spectrum.The reflection spectra of the FBG subjected to the transverse force split in two main peaks,and the split point shifted linearity and periodically versus the applied force.The split point was shifted in the bandwidth with the period of 11 N,and in one period the sensitivity of the split point wavelength shift versus the applied force was 0.05 nm/N.The experimental consequents show agreement with the simulation analysis.