The testing method for imaging quality of visible light systems has been applied in infrared optical systems. A device for testing the imaging quality of infrared optical systems has been developed. With the control of 486DX2/66 computer, the device can implement data acquiring, storing and processing of images produced by an infrared optical system. The imaging pictures in different colors or gray levels can be shown on the display screen. It can also test the energy distribution of imaging pictures of various infrared optical systems.