Frequency shift effect in photonic crystals modulated by shock wave was studied.The physical model of one-dimension photonic crystals modulated by shock wave was built.Quasi-static bandgap structure was put forward,and its bandgap was calculated using Finite-difference Time-domain (FDTD) and Pulse Width Modulation (PMW).By performing numerical computation and perturbation analysis,the incidence frequency increased by integral multiple of a certain amount in the process of frequency conversion was found,and photon-phonon interaction and surface decaying mode interpretation for the mechanism of frequency shift was put forward.The characteristic of frequency shift effect was also analyzed.