The bistabilities and resonant modes of the square lattice and triangular nonlinear photonic crystal cavities with Kerr media were numerically simulated using finite-difference time-domain（FDTD） algorithm

based on the theoretical model which described the interaction between the Kerr medium and light field.The triangular nonlinear photonic crystal cavity with multiple Kerr defects showed multi-mode resonant frequency

which in a wide range kept the output optical intensity in high transmittance level.The photonic crystal structure with this bistability property gave reference to the design of all-optical networks.