To improve the safety and automation during the spanning construction of transmission lines with voltage levels of 110kv and below, an intelligent spanning frame monitoring system based on PLC and configuration software is developed. The system performs real-time monitoring and early warning of various parameters such as height, inclination, and wind speed at the construction site of the spanning frame during the construction process, and controls a series of actions such as the synchronous lifting and spanning of the crossing pole, and the insulating mesh distribution and net collection. The system adopts the distributed structure of a monitoring center and four substations to realize distributed hybrid networking by combining wireless communication, serial communication, and 4G communication.