Laser active imaging technology such as range-gated imaging can solve problems like deep space target detection,night vision,etc.However,when usinglinearly polarized light or circularly polarized light to illuminate the targets so as to capture the images,there will be obvious speckles which usually causedby the rough surface of the targets and the disturbing of the cloud and the atmosphere,especially for the remote small target detection,it will distort to alarge extent and then the target details will be lost.