To solve the problem of the substrate’s slow thermal conduction for flexible temperature sensors to quickly monitor the temperature of bearings and other curved surfaces, high thermal conductivity composites were prepared by doping 3% wt graphite (GR) into polyimide (PI), which reached a thermal conductivity of 0.777 W m-1 ^K-1 and had good insulation properties. Based on the microfabrication technique, Pt film flexible temperature sensor was prepared on the GR/PI composite film, and its dynamic response characteristics were improved with the response time of 71 ms, which is better than that of the Pt film flexible temperature sensor on pure PI substrate. In addition, the electrical properties such as linearity, sensitivity and measurement repeatability are good. The prepared sensor was used for temperature measurement on metal shaft surfaces, and the difference between the measured values was small (within ±2°C) compared with a commercial infrared camera.