Abstract: Aiming at the shortages in traditional personnel positioning systems like low positioning accuracy，not clear positioning expression，and only regional positioning，a personnel positioning system in 3D coal undergrounds is proposed based on WiFi and VR technologies.The structure，working principle，system function and key technologies of this system are introduced.To improve positioning skills and three-dimensional expression performance of the system，real-time calculation of 3D coordinates of underground personnel and an improved camera occlusion detection algorithm are designed，and the prototype three-dimensional space personnel positioning system is built based on Unity3D engine and the 3ds Max modeling tool，realizing the functions of personnel information management，three-dimensional real-time positioning，path query，violations supervision，which can provide support for post-disaster relief，production scheduling，attendance management and so on.Taking a coal mine in Shanxi as a trial，error of the system is controlled within 3 m by underground experiments，and personnel real-time location and surrounding environment are visible in the camera，which verifies the feasibility of locating algorithm.The system has been applied in practice with a good effect.

Key words: 3D Scene, Roadway, Personnel Positioning, GIS