Nonlinear effect of infrared imaging system has a big influence on infrared imaging quality,and it is also the key of restricting target identification precision,how to simulate imaging system nonlinear effect in real-time and efficiently has become a hotspot and difficulty in 3D infrared scene simulation at present. A dynamic adding method of imaging system nonlinear effect in infrared simulation scenes was presented,and computational process of typical nonlinear effects were analyzed,such as vignetting effect,distortion effect,noise effect,out of focus,etc. “lens” were attached to simulation view by using the technology of render to texture(RTT),then nonlinear effect was simulated in “lens” through vertex and fragment shader based on Unity platform,and overlaying calculation was conducted with zero stadia infrared simulation scenes,thus dynamic simulation of nonlinear effect was realized . The experiment results indicate that the method has high reality,reliability and lower simulation cost,and it can meet the demand of real-time simulation in imaging system nonlinear effect.