Using Mueller matrix element of parameters to represent the depolarization of one object,experimental device is designed to measure the depolarization degree of two types of coins according to the relation of the Stokes-Mueller matrix.Then active imaging experiment is carried out on the two coins,using linear polarized laser as light source and CCD camera as the imaging detector.In the experiments,an image without check polarizer and six polarization images with different polarization angles are collected.Experimental results show that the polarization image technique with appropriate polarization angle can effectively improve the image contrast,which is helpful to distinguish different targets.