In this study, a high-sensitivity temperature sensor based on surface plasmon resonance (SPR) is designed by plating gold thin layer and PDMS temperature-sensitive film onto the outer layer of photonic crystal fiber (PCF). It has the advantages of a simple structure, mature process, and good reversibility. The refractive index of PDMS decreases with the increase in temperature, causing the loss peak of the core mode to move toward the short-wave direction. The full-vector finite element method is used to analyze the SPR-PCF loss spectral characteristics under the condition of a perfectly matched layer boundary, which can achieve highly sensitive and accurate temperature measurements. The temperature sensitivity of the proposed sensor has been observed to reach -8.18 nm/℃ within the temperature range of 22--47 ℃. Furthermore, the proposed measurement method is applicable in safety detection and intelligent monitoring fields.