Based on the vernier effect of the parallel interference filter,we propose a fiber optic temperature sensor based on the paralleled structure of the fiber Sagnac interferometer (FSI) and the Mach-Zehnder interferometer (MZI).The FSI consists of a 3 dB four-port coupler and a 6.6 m polarization maintaining optical fiber (PMF).Because of its higher sensitivity and better stability,it is used as a sensing cavity.MZI as a reference cavity consists of two 3 dB three-port couplers self-made,by controlling the length of the two arms of MZI,so that the free spectral range (FSR) of the two interferometers is close but not equal,the vernier effect is used to improve the temperature sensitivity of the structure,and then by changing the temperature to measure the wavelength drift of a single FSI and paralleled FSI,MZI,so as to explore the amplification of temperature sensitivity.Experimental results show that the temperature sensitivity of a single FSI is only －1.65 nm/℃,and the paralleled system can amplify it to 12.9 nm/℃ with a gain coefficient of 7.82,which is consistent with the theoretical results,indicating that the paralleled structure can significantly improve the sensitivity of the temperature sensor at the same temperature.And the proposed sensor has significant wavelength drift while a smaller temperature changing which is suitable for fine temperature detection in biological and industrial fields.