The invention discloses a safety monitoring system used in a power lines repairing operation and an operating method based on the safety monitoring system, belonging to the technical field of power distribution system maintenance. The safety monitoring system comprises a remote terminal, a signal reception tower, a server, an Internet, a power supply module, a safety monitoring module, a dispatching center, a production technology center and a plurality of on-site terminals, wherein the on-site terminals are wirelessly connected with the remote terminal; the remote terminal is connected with the server through wireless signals; data received by the server is transmitted to the power supply module, safety monitoring equipment, the dispatching center and the production technology center through the Internet respectively; transverse information sharing or information inter-transmission among the power supply module, the safety monitoring module, the dispatching center and the production technology center can be realized, and each of the power supply module, the safety monitoring module, the dispatching center and the production technology center can send instructions to the on-site terminals for implementing the power lines repairing operation through steps of preliminary judgment on malfunction, dispatching of working staff, examining and repairing and the like. Closed-loop management is implemented in the technical scheme, therefore, the whole maintenance process is subjected to standardization, flow processing and form processing; effects of reinforcing on-site management and control and eliminating on-site potential safety hazards are achieved.