Based on the vernier effect of the parallel interference filter,we propose a fi ber optic temperature sensor based on the paralleled structure of the fiber Sagnac interfero meter (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 bette r stability,it is used as a sensing cavity.MZI as a reference cavity consists of two 3 dB three-port coup lers 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 temperatu re to measure the wavelength drift of a single FSI and paralleled FSI,MZI,so as to explore the amplification of tempera ture sensitivity. Experimental results show that the temperature sensitivity of a single FSI is on ly －1.65 nm/℃,and the paralleled system can amplify it to 12.9 nm/℃ with a gain coefficient of 7.82,w hich is consistent with the theoretical results,indicating that the paralleled structure can significantl y improve the sensitivity of the temperature sensor at the same temperature.And the proposed sensor has sig nificant wavelength drift while a smaller temperature changing which is suitable for fin e temperature detection in biological and industrial fields.