An optical fiber temperature sensor based on surface plasmon resonance (SPR) is designed. The ends of a single-mode fiber and a multi-mode fiber are ground into wedge shapes and spliced. The gold film with a thickness of 50 nm is plated on the polished surface of this single-mode fiber to form the Kretschmann configuration. Then a layer of polydimethylsiloxane (PDMS) is coated as temperature sensitive medium and thus temperature sensing is realized. The experimental results show that the maximum sensitivity of this sensor can reach 4.15 nm/℃ when temperatures are between 20 ℃ and 70 ℃, much higher than those of other types of optical fiber temperature sensors. Compared with other SPR-based optical fiber temperature sensors, this sensor has a much narrower full width at half maximum and a larger figure of merit. In addition, this sensor has a relatively high stability with the maximum temperature standard deviation of 0.14 ℃. This sensor has a simple structure and low cost, and is expected to be widely used in the industrial field.