Laser range-gated scan-type imaging technology has the advantages of lower cost and multiple scattering reduction. Synchronous operation between imaging scan and laser-beam scan is the technical difficulty in the scanning imaging technology. Herein, a scan-type range-gated LiDAR system based on spatial light modulator (SLM) is designed to temporally and spatially shield backscattered light while ensuring the reliable receipt of reflected light from the targes. Measurements are performed in light scattering environments with different attenuation lengths to realize the 2D and 3D imaging implementations. Experimental results show that the synchronization between light-beam scan and range-gated imaging scan can be effectively achieved in this system. Moreover, the proposed system is applicable to visible-range extension of optical imaging in a light scattering environment.