Abstract:The images which were acquired by underwater rangegated imaging system have degradation for the reasons of scattering and absorption of water. To advance the quality and overcome the disadvantage of common histogram equalization,a new method was proposed based on analysis of characteristic of underwater laser imaging .After filtering by edgepreserving smoothing, it split the histogram,the parts of high gray and low gray were equalized separately,and then combinated. The experiment shows that the method proposed above is very effective in enhancement of underwater laser imaging to restain background noise,clear object details and advance contrast.