In order to improve the density and capacity of the fiber Bragg grating sensor network,it is proposed to introduce the ultrasonic pulse p wave into the fiber,which will affect the spectrum of the fiber Bragg grating in the propagation process,so as to mark and distinguish the fiber Bragg grating.The influence of different excitation signal parameters on the spectrum of fiber Bragg grating was studied.The propagation process of ultrasonic pulse p wave in the fiber was simulated by ANSYS software.The modulation model of ultrasonic pulse p wave to the spectrum based on the coupling theory of Fourier mode was established,and the model was simulated and analyzed.The simulation results show that,compared with trapezoidal pulse,the modulation amplitude of Gaussian pulse is reduced by 12 pm under the same conditions,but the modulation stability is better than that of trapezoidal pulse.Reducing the pulse width of Gaussian pulse will improve the modulation amplitude,but too small the pulse width will cause strain trailing and reduce the modulation effect.Under the conditions described in this paper,the modulation effect of 34 μs pulsed Gaussian p wave is the best,which can ensure the modulation amplitude of 82 pm and make the central wavelength redshift and blue shift respectively.The simulation results provide a reference for the selection of excitation signal parameters with ultrasonic pulsed p wave and lay a foundation for distinguishing fiber Bragg grating by ultrasonic pulsed p wave.