This article introduces the principle of single?photon Light Detection and Ranging（LiDAR） system, elaborates on the composition and core device characteristics of single?photon LiDAR system, and discusses the advantages of single?photon LiDAR technology such as photon?level sensitivity and picosecond level time accuracy. From the perspectives of hardware improvement and algorithm improvement, optimization methods for single?photon LiDAR systems were analyzed. The applications of single?photon LiDAR technology in ground?based long?range target imaging, aerospace remote sensing, and complex scene imaging were explored, and the future development direction of single?photon LiDAR technology was prospected. It was pointed out that the detection efficiency, dark count rate, time jitter, and power consumption can be improved by expanding the detector response band, optimizing device design, and applying new materials; Advanced algorithms can be utilized to achieve deep information mining, and improve detection accuracy and real?time performance; Single?photon LiDAR technology can be combined with other advanced technologies to expand its application scope.