Footprints found at a crime scene are very difficult to use to narrow the scope of identifying a suspect or to clarify the direction of an investigation. 3D scanning (microscopic), which could be more effective than 2D imaging in reflecting the detailed features of footprints, still involves high hardware costs and an exponential increase in calculation capacity owing to the large size of 3D files. To solve these problems, a single-point laser 3D footprint detecting system was designed and developed. The key technologies in this system, such as feature extraction and similarity comparison, are described in detail. Finally, the experiment results of 3D footprint inspection demonstrated the accuracy and reliability of this system.