In this paper, a novel all-fiber temperature sensor based on Fabry-Perot interferometer (FPI) and Michelson interferometer (MI) is proposed and fabricated. The sensor is formed by sequentially fusion-splicing a single-mode fiber, a segment of suspended-core fiber (SCF), and another segment of single-mode fiber, with each connection having an offset. The reflecting surfaces formed by the fusion and cutting constitute the FPI and MI, and the optical path of MI is about 2 times (slightly more than 2 times) that of FPI, so the two interferometers produce the first-order harmonic vernier effect. The experimental results show that the double envelopes with obvious first-order harmonic Vernier effect appears in the interference spectrum of the sensor, and with the increase of temperature, the double envelopes of the interference spectrum gradually red-shifts, and the red-shift amount is much greater than that of a single MI. In the temperature range of 20 ℃~120 ℃, the temperature sensitivity of the sensor is 208 pm/℃, about 20.8 times that of a single MI, and about 245 times that of a single FPI. The temperature rising and falling experiments and multiple measurement experiments at the same temperature show that the sensor has good repeatability and stability. The sensor realizes the parallel connection of FPI and MI within the same optical fiber, with a total length of the sensor head being only about 584.4 μm. Additionally, it features an all-fiber tip structure, making it particularly suitable for high-temperature detection in small space environments.