Because of work at all day and all weather, radiometer can provide the specific information which infrared and optical detectors can′t provide. However it is urgent to improve the image resolution. On basis of studying the fusion algorithm for multisensor, a new approach to fuse the millimeter wave measuring image and optical-based simulated image by wavelet transform is presented. The simulation result shows that fusion image has more complementary information than the measuring image and possesses higher resolution as guidance matching map.