The detection and maintenance of the railway contact network is very important for the safe operation of the railway. How to detect the current state of the contact network automatically, quickly and accurately has become an urgent problem to be solved by the construction, operation and maintenance departments of the contact network. In this paper, a patrol inspection robot that can walk freely on the contact network and detect the vibration frequency of the contact network is designed. Combined with the microprocessor with 51 single-chip microcomputer as the core and bluetooth wireless communication module, the vibration frequency detection and control system of the contact network is established. In order to verify the feasibility of the system design scheme, the railway contact network is taken as the detection object to complete the detection of its internal vibration frequency. The experimental results show that the vibration frequency of the contact network can be detected successfully by this detection control system, and the internal damage of railway catenary can be preliminarily judged. Compared with other railway contact network detection methods, this detection and control system is simple and versatile, and it has certain reference value.