With the development of detectors, 3D imaging lidar system can obtain distance, intensity, distance-angle image of objects by combining the advantages of active and passive detection. The produced images provide much decision information for proper identifying and tracking object so that target recognition probability and reliability are improved. Firstly, current development state of 3D imaging lidar system is introduced, which focuses on Gen-III system in Lincoln library and 3D flash laser radar system in Autonomous Precision Landing and Hazard Detection Avoidance Technology (ALHAT) by NASA. Next generation of 3D imaging laser radar systems is described through analyzing the characteristic of HgCdTe avalanche photodiode (APD) detector. Finally, the developing prospects of the active/passive detector technology in 3D imaging lidar systems are outlined．