For the single frame image enhancement, the enhancement of weak small targets has some limitation with only using partial information of target both in time domain and the spatial domain. The spatial domain processing methods focus on the gray feature of image target, its shortcoming is to ignore the gray continuity of the target in the time domain. However, the time domain processing methods take into account the gray continuity of the target in the time domain, but ignoring the gray intensity distribution, which will result in recognizing too many false targets with the interference of noise. The purpose of the spatial domain processing and time domain processing is to enhance target on the different basis. The spatial domain processing has a focus on the spatial characteristics of targets; another has a focus on the time movement characteristics of the target. Therefore, the energy enhancement method of multiple frames target combined with the time domain and spatial domain attract more and more attention. In this paper, according to the different feature of the target and the background and noise in space domain and time domain, the joint probability distribution is adopted to integrate gray image obtained by the two processing methods. Studies show that the average grey value and SNR gain of target enhance effectively after enhancement. At the same time, due to the time domain and spatial domain processing independent of each other, parallel processing method can be used in order to improve the speed of processing and greatly shorten the operation time.