In this paper, a fiber-optic interferometer based simultaneous measurement of temperature and transversal loading by using dual-passband microwave photonic filter (MPF) has been proposed and experimentally demonstrated. The modified fiber Mach-Zehnder interferometer (FMZI) based sensor is used as the spectrum slicer, and along with the dispersive medium, dual-passband MPF can be realized. The changes on the FMZI will affect the transmission spectrum, and then the frequency response of the dual-passband MPF. In the experiment, the proposed method has been adopted for simultaneous measurement of temperature and transversal loading. One arm of the modified FMZI can be used for the temperature sensing, and the fiber between two outputs of the FMZI can be utilized to measure the transversal loading. By tracking the central frequency and the peak power of the passbands of the MPF, temperature and transversal loading changes can be demodulated.