The utility model relates to an intelligent transmission line monitoring system, and specifically relates to a monitoring system for transmission lines, comprising a main controller (1), a detection device, and a multifunctional communication module (9). The main controller (1) is specifically a single chip microcomputer. The detection device is connected with the main controller (1) through an input module (2). The detection device comprises a pan-tilt-zoom camera (3), an infrared transmitter (4), a receiver (5) and a laser range finder (6), wherein the infrared transmitter (4) and the receiver (5) are respectively mounted to corresponding positions of adjacent two base towers, and the laser range finder (6) is mounted at the upper end of the towers. The monitoring system for transmission lines of the utility model is simple in structure and convenient to use. The safety of transmission lines is effectively improved. The problem that damage of external force to transmission lines cannot be easily found through daily inspection of the power supply department and quick settlement of and response to the damage cannot be realized is solved.