An all-fiber Mach-Zehnder interferometer (MZI) temperature sensor based on the inter-modal interference principle is proposed and experimentally demonstrated. According to the simulation results of the MZI based on core-offset, we optimized the structural parameters of such an MZI sensor. The MZI sensor based on core-offset with the extinction ratio of more than 20 dB is obtained successfully. The performance of sensing temperature of such MZI sensors is tested. The influence of the interference length and bending structure of such MZI sensors on the temperature response are also investigated in detail. The temperature sensitivity is improved and reaches to 116 pm/°C.