A safety network system is designed based on PROFIBUS-DP field bus, according to actual servicing work situation and control requirements for electric locomotive servicing work. The system realizes communication between first class master station and third equipment through using PROFIBUS-DP bus protocol. It also realizes interactive operation between slave station and non-contact IC card, meanwhile, slave station and MCU system. In addition, this article has analyzed the multi-task scheduling mechanism and data communication security on monitoring network system in detail as well. Results show that the system has higher application value through entire debugging and testing on network control system.