In recent years,researchers have referred to the Vernier structure in calipers and barometers.In the multi-wavelength fiber laser sensor,the dual interferometer cascade is used to generate the Vernier effect,which is used to improve the sensitivity of the sensor.In this paper,through simulation and experimental testing,the Vernier effect generated by the cascade of fiber Sagnac interferometer (FSI) and fiber Fabry-Perot interferometer (FFPI) is studied Two kinds of temperature sensors with different structures wer e designed,and the effects of the cascade structure on the temperature sensitivity of the sensors were studied thr ough experimental tests.The results show that the temperature sensitivity is increased from －1.7nm/℃ (FSI tempe rature sensing sensitivity) and 0.008nm/℃ (FPI temperature sensing sensitivity) to 10.28nm/℃ and 10.64nm/ ℃,respectively.Based on the Vernier effect,the sensitivity of the temperature sensor is increased by more t han 6times.The experimental results are basically consistent with the theoretical analysis (10.82nm/℃).