Abstract: To increase the fidelity of infrared staring focal plane array(FPA) detector-s imaging simulation, we analyzed the mechanism of spatial sampling effects in the IRFPA detector,built the model in spatial region,and carried out the simulation experiment based on pixel processing method. In order to objectively evaluate the spatial sampling effects on the detector imaging quality,it defined a negative index of image smoothness. The experimental results show that the smoothness of the detector output image with spatial sampling effects is reduced by 11.7%, and the local fluctuation of image is larger, which verifies the necessity of considering the sampling effects in IR detector imaging simulation.