This work fabricates and demonstrates a temperature sensor with high sensitivity and an expanded measuring range based on the microfiber knot resonator. Multiple-modes are generated in the microfiber knot resonator and participate in the resonance. The spectra of multiple mode resonance is superimposed on each other to form a vernier spectrum with envelope. By extracting the envelope of the vernier spectrum, high-sensitivity temperature measurement can be achieved with the sensitivity of up to - 10 nm/ ℃ . However, the temperature measurement range using the vernier spectrum is calculated to be only about 4℃ . To solve the problem of too small measurement range, the envelope spectrum and single frequency component spectrum are combined to expand the measurement range to about 20℃ . Compared with the resonance spectrum corresponding to the single frequency component, the vernier envelope spectrum achieves an amplification of sensitivity of about 1 600 times. This scheme uses the vernier effect to improve the sensitivity of temperature measurement. Meanwhile, the temperature measuring range of the vernier spectrum is expanded by using the resonant spectrum corresponding to a single frequency component, which improves the performance and practicability of the sensor.