When the spacecraft reenters the earth atmosphere, the outer surface of spacecraft will generate megawatt of heat flux. As a result, the instantaneous temperature rise can reach 1800℃ . In order to ensure the stability and safety of the spacecraft, it is significantly important to accurately measure the heat flux on the thermal protection system surface of the spacecraft in real time. Aiming at the technical difficulty of heat flux measurement in high-temperature condition, a novel heat flux sensor structure integrating the lead and substrate is proposed. Combining the ceramic sintering static pressing molding and magnetron sputtering technologies, a new high temperature thin film heat flux sensor was developed by sequentially depositing PtRh30-PtRh6 thermopile thin film, Al 2O3 film and ZrO2 film on the substrate surface of 99 alumina ceramics where the PtRh6 leads are embedded. Then, the static and dynamic performance, high-temperature resistant and repeatability tests were conducted. The result shows that the sensitivity of the sensor reaches better than 0. 01 μV/ (W/ m 2 ), the dynamic response time is 3. 97 s. High temperature test at 1200℃ was conducted on the sensor, the test result shows that the output signal of the sensor has no obvious change before and after the high temperature test, and the maximum repeatability error is 2. 38% . The developed high temperature thin film heat flux sensor can provide scientific basis for the high temperature heat flux measurement and thermal protection system optimization.