Based on the principle of inter-mode interference,a Mach-Zehnder interferometer (MZI) sensor composed of Panda polarization maintaining fiber (PMF) is fabricated in this experiment.Because of the coupling of the large aperture multimode fiber (MMF),the sensor shows high sensitivity to temperature.When the external temperature changing,the transmission spectrum of the sensor shifts.By observing the wavelength shift of characteristic peaks,the temperature response characteristics of the sensor is obtained.From the experimental data,the wavelength of two characteristic peaks of the SMF-MMF-PMF-SMF interferometer structure linearly responses to temperature.The sensitivity of temperature is －123.80 pm/℃ and －195.20 pm/℃,respectively.The repeatability and stability of this sensor for temperature measuring are very good,and this sensor can effectively measure the ambient temperature.