Compared with two-dimensional imaging, three-dimensional (3D) LiDAR imaging has the advantages of rich information, good initiative, and strong anti-interference ability, and it has been widely used in reconnaissance, unmanned vehicle, aerospace, etc. Recently, 3D LiDAR imaging developed rapidly from two aspects. On the one hand, the manufacturing capability of APD as a typical core device has been improved, and the imaging efficiency of LiDAR has been significantly increased. On the other hand, with the continuous improvement of 3D imaging methods (scanning/non-scanning), their comprehensive performance has also been dramatically improved. This paper provides support for advancing the application of 3D imaging by summarizing the current research status of 3D LiDAR imaging, discussing the problems and proposed solutions faced in the present stage.