Based on the infrared equipment field test, many system measurement parameters can be obtained。 An effect simulation of infrared imaging system is proposed to be made on the basis of the system measurement parameters. For the infrared imaging system, the aberration effect, defocus effect, space integraling effect and noise distribution were analyzed, and the optic system effect and detector effect were simulated respectively. The result of imaging simulation was given in combinition with the test parameters of infrared system.