The real-time maintenance sensor for the active reflector is one of the key technologies for the active reflector upgradation plan of 13.7m millimeter radio telescope from Purple Mountain Observatory, China. A new type of maintenance integration sensor based on PSD and laser module based on normal angle and distance detection is proposed in this paper. After the brief introduction of the maintenance theory of the radio telescope segmented primary reflector, the method is simulated and tested on the real backup panel from the telescope in the active reflector lab in Nanjing Institute of Astronomical Optics and Technology, China. The method is proved to be a high accurate, engineering feasible for that real-time maintenance of the whole primary. Finally some conclusions are reached.