During the study of nonuniformity correction algorithms for Infrared Focal Plane Arrays (IRFPA), a large number of target images containing nonuniformity information need to be obtained by simulation. According to the generation mechanism of nonuniformity of IRFPAs, a detection element nonuniformity model, a readout circuit nonuniformity model and a drift noise model are established respectively. By superposing the nonuniformity of the three models on the ideal image respectively, the target image is obtained eventually. In the process of simulation, it is assumed that the nonuniformity noise obeys the Gaussian distribution. By setting the model coefficients with different mean and variant, different degrees of nonuniformity simulation can be achieved. Because the drift noise is considered, the simulation results of the proposed method are more consistent to actual situation.