A thin film thermocouple sensor directly deposited on Ni-based superallo is studied in this paper. According to the high temperature and harsh environment of aero-engine, the layer structure of the sensor is designed. Using the magnetron sputtering technology to deposite the membrane transition layer of NiCrAlY, the thin film insulating layer and protective layer are fabricated by the method of E-beam evaporation and RF-magnetron sputtering techniques. The Pt10Rh/ Pt sensitive layers of thin-film are prepared by DC magnetron sputtering technology. Test results show that the maximum operating temperature is 1 100 ℃. The seebeck coefficient is 8.26 μV/℃. The maximum temperature error is 0.93%. The service life is over 20 h. The results show that the thin-film thermocouple can withstand the harsh test environment of aero-engine, and the accuracy of the measurement’s local temperature is improved. The important basis for the life expectancy of the turbine cascade and the design of cooling structure is provided.