With the increase of radio transmission rate, the visible images and the infrared images acquired by UAVs can be downloaded to the ground station at the same time, and more battlefield information can be obtained based on the fusion of the two kinds of images.The existing technology relies on the method of digital image processing, which requires a large computation cost and high performance of hardware.To solve this problem, the system uses two DM642 as the main CPU to process the infrared images and the visible images respectively.Firstly, the target features of the designated area in the infrared image are extracted, and then the geographic coordinates of the target area in the infrared image are calculated by using the attitude information from the UAV and the airborne camera, and converted into the screen coordinates of the visible image.Then, the target is corrected according to the installation angle and field-of-view angle of the visible-light camera and the infrared camera, and the infrared target is fused into the visible image according to the method of maximum pixel gray level.The result of flight tests show that, the system has fast image fusion speed, accurate target fusion position, which meets the requirements to the system.