Abstract: In order to meet the requirement of monitoring temperature change during the NaCl solution concentration measurement, an interferometric sensor based on Mach-Zehnder interferometer(MZI) cascaded Fabry-Perot interferometer(FPI) was proposed. The MZI was prepared by melting and splicing a single mode fiber to form a pair of tapers structure with diameter of 155 m at the waist an interval of 1.5 cm and the contrast and period of the MZI was 10 dB and 29.85 nm, respectively; Then a photonic crystal fiber (PCF) was spliced to one end of the MZI, cleaving the PCF at a distance of a 176 m from the splicing position, which a FPI was formed with contrast and period of 8 dB and 5.71 nm, respectively. By selecting the characteristic wavelength shifts of MZI and FPI interference dips in the range of 1 535-1 555 nm, in the temperature range of 30-150℃ and NaCl solution concentration range of 0%-24%, the temperature and refractive index sensitivities were 50 pm/℃ and 9.97 nm/RIU, respectively. The linearities were both greater than 0.97; While the interference dip of FPI was insensitive to the refractive index, and its sensitivity of temperature and linearity was 8.3 pm/℃ and 0.98, respectively. Finally, the sensitivity matrix for temperature and NaCl concentration was calculated by constructing the temperature-NaCl concentration function matrix. The interferometric sensor has good sensitivity and linearity to temperature and concentration of NaCl solution, which can realize the simultaneous measurement of the mentioned parameters.