Regarding the issue of unclear degree of influence of rocket engine flame on simulated dummies in performance tests of a certain type of aircraft. This article proposes an airborne instantaneous temperature measurement system based on K-type thermocouples, and analyzes the common measurement errors and influencing factors of K-type thermocouples. The airborne instantaneous temperature measurement system uses a thin K-type thermocouple with a thickness of 0.02 mm and a KAM-500 telemetry acquisition system, which can achieve high-speed acquisition of millisecond level temperature changes. Research has shown that the average response time of the K-type thermocouple used in this system is only 16 ms. Moreover, the reliability of the instantaneous temperature measurement system has been verified through performance tests of a certain type of aircraft, providing data reference for airborne instantaneous temperature measurement technology.