The propagation characteristics of one-dimensional photonic crystal with inhomogeneous Kerr medium were studied, and a new algorithm for dealing with nonlinear part of the layer was created. It’s very convenient to simulate the transfer behavior of one-dimensional Kerr medium. Optical bistable switching of 1D photonic crystal with Kerr defect was investigated by this method, and the results were well in line with those of sub-layer recursive reverse transfer matrix method. Moreover, the new method exhibits simple, rapid and easy-to-understand.