A scannerless 3D imaging laser radar is developed. A pulsed solid state laser is used as source with image intensified CCD (ICCD) as imaging detector. When the laser source transmits light pulse to a target scene, the image intensifier of ICCD is modulated with the monotone time-variant high voltage. High voltage signal controls the image intensifier to produce the monotone time-variant gain modulation, which leads to different amplification factor on return light reflected from different range. By analyzing and comparing the energy of amplified signals, we can calculate the flight time of every return light and then get the range of the corresponding target. Results demonstrate that the system can effectively eliminate the effect of non-uniform of the return light intensity. An indoor imaging experiment is performed for demonstrating the feasibility of system, and range image of targets from 35 to 41 meters distance is successfully acquired and the range accuracy can be less than 1 meter.