The invention provides a transmission method of the monitoring information of a power transmission line which is capable of preventing the congestion of a wireless sensing network. According to the transmission method provided by the invention, the communication subsystem which is composed of a signal acquisition board, a wireless module and a server in the power transmission line monitoring system is divided into seven layers logically, which are respectively an application layer, a presentation layer, a session layer, a transmission layer, a network layer, a link layer and a physical layer; congestion-resistance measures are adopted simultaneously in the link layer, the transmission layer and the application layer of the ZigBee communication protocol, wherein the data transmission rate is adjusted in real time by the link layer according to the duty cycle of the network; a QoS classification service is adopted by the transmission layer to ensure the real-time transmission of key signals; and the application layer adopts the methods of alarm summary, alarm queuing, and specific alarm data calling based on the queuing, so as to avoid congestion of the channel caused by the direct uploading of a large number of specific alarm data. By adopting the transmission method provided by the invention, the congestion of a wireless sensing network of the power transmission line monitoring system can be effectively prevented, and the key monitoring information can be guaranteed to be uploaded timely.