The fundamental principles of single-photon imaging technology are introduced, along with an analysis of its advantages of high sensitivity, high temporal resolution and high photon utilization efficiency. The technical characteri-stics of single-point scanning and multi-pixel single-photon imaging are elaborated, with discussions on their applications in scenarios such as long-range imaging, underwater imaging, and imaging in complex environments. Principles of traditional single-photon imaging algorithms and deep learning-based algorithms are presented, followed by a comparative analysis of their application effects under conditions of sparse echoes, strong noise and multi-peak signals. The outlook for the future development of single-photon imaging technology is proposed, highlighting that innovative hardware systems, optimized imaging algorithms and interdisciplinary technology integration will further advance the field toward higher accuracy, efficiency and intelligence.