Range-resolved laser reflective tomography is of great potential application in obtaining image information about an object with non-imaging laser radar system. The resulting time-dependent return signal which collected by non-imaging laser radar system provides one-dimensional raw projection data for reconstructing target image. However, this return signal can be regarded as the multi-convolution between the distribution function of target reflectivity, atmospheric transmission, detection circuit response and acquisition circuit response with the emitted laser pulse signal. In order to efficiently improve the reconstructed target image quality using short pulse laser, this paper presents a method used to restore the impulse response of target reflectivity modulation from the resulting time-dependent return signal so as to improve the reconstructed target image quality. This method is based on sending the laser and making it vertically irradiate to a profile of target in the front view to obtain basic wave pulse, then used it to recover the response of target reflectivity modulation. The experiment results show that this method is feasible and efficient.