A miniaturized optical fiber tip Fabry-Perot interferometer for high-temperature measurement is presented in this paper. The fabrication process of the diaphragm-free Fabry-Perot cavity is quite simple, involving only two steps: fusion splicing and cleaving. By adjusting the arc power during fusion splicing, a concave-shaped structure is obtained, through which the light is coupled/split into the wall of the spliced hollow core fiber. By cleaving the end-face of the hollow core fiber, a concave-shaped diaphragm-free Fabry-Perot interferometer is formed. The temperature response of the sensor was demonstrated, showing a high-temperature tolerance up to 1000 °C and a sensitivity of 0.01226 nm/°C.