In order to meet the requirement of real time monitoring of multi aircraft training in the same field in flight test, a telemetry transmission system based on network radio is designed. According to the structure and characteristics of wireless Mesh network, the key technology of wireless Mesh network applied in telemetry transmission is analyzed by using network topology structure. The telemetry transmission system based on network radio is designed and verified its effectiveness by flight test. The test results show that the system can realize the real time transmission and display of key data such as position, speed and track of multiple aircraft. It has high reliability and can meet the requirements of real time close-range monitoring and command of multiple aircraft in fight test.