Laser range-gated active imaging under atmospheric conditions for stationary target imaging has the advantages of high resolution,long-range,etc. For moving target imaging,in order to track the moving targets,the distance gate width should increase,and then cause backscattering. The active imaging system based on laser range-gated is analyzed,and the range information is introduced to track moving target in real time on this basis. The effect of backward scattering caused by different gate width on image quality is studied. The lifting wavelet transform is adopted to introduce homomorphic filtering,and the noise caused by the backward scattering is as the low frequency components,and then the wavelet coefficients are processed by using high-pass filtering. The results show that,the algorithm achieves good backward scattering suppression effect,and basically eliminates the backward scattering effect,which makes the backward scattering noise ratio of the whole image reduce from 66% to 1%.