Fiber-optic intrinsic Fabry-Pérot interferometric (IFPI) sensor, fabricated in standard single-mode fiber with femtosecond (fs) laser, which can be used for high temperature measurements is proposed. The fiber-optic IFPI sensor consists of a pair of internal reflectors inscribed by the femtosecond laser and the in-cavity fiber. The fringe contrast of the reflection spectrum of the sensor reaches 10 dB and the insert loss is only 0.1 dB. The experimental results show that the measurable temperature of this sensor is up to 1000 ℃ and the temperature sensitivity is 14.9 pm/℃. The repeatability of the reflection spectra is very high in many measurements, which indicates that the sensor can achieve accurate measurement of high temperature. The sensor is simple, low-cost and easy to connect to the existing fiber-optic devices, so it suits for fiber-optic sensing network and has a great value in engineering.