The paper proposed and studied a Fabry-Perot interferometer (FPI) sensor by splicing a photonic crystal fiber (PCF) to a well-cleaved single-mode fiber (SMF), preparing a SMF-PCF-SMF structure, and the section of PCF was the cavity. The spectrum wavelength interval was 2.18 nm and its contrast was up to 13.12 dB. Temperature was investigated experimentally in the range of 50 ℃ ~ 400 ℃ with temperature-rise and temperature-drop process. The temperature sensitivity is 12.3 pm/℃ and its linearity is greater than 0.993. The proposed sensor could offer some excellent features such as low cross-sensitivity, good temperature stability and linearity, making it attractive in the areas of industrial production, aerospace and biomedicine.