With the continuous improvement of gas turbine, its blade temperature is getting closer to the temperature tolerance limit of materials. However, the current temperature measuring instruments on the market cannot accurately reflect the blade temperature and distribution. To solve this problem, a scanning radiation temperature measuring system is designed. When the system is working, the probe is installed on the engine casing and aimed at the surface of the blade. The infrared radiation emitted by the blade is reflected by the reflector at the front end of the probe and enters the probe. It is transmitted to the controller through the optical fiber at the end of the probe, and the optical signal is processed and converted into a temperature value. Through the coupling simulation of the flow field and the temperature field of the scanning probe, the results show that the whole probe can be effectively protected in the engine when 25 ℃ cooling gas is introduced at a flow rate of 0.1 kg/s and the probe detection time is not more than 15 s; the fluid pressure at the end of the probe is about 17.0 MPa, which is much higher than the gas pressure of 1.4 MPa, so this area can isolate the high-temperature gas to prevent it from entering the probe and contacting the reflector. Experiments were carried out in the laboratory to verify the system. The results showed that the repeatability and stability of the probe at each temperature point did not exceed 7.5 ℃,that the temperature measurement system can meet the needs of turbine blade surface temperature measurement.