An arrayed electrically tunable infrared (IR) filter based on the key structure of liquid crystal Fabry-Perot (LC-FP) working in the wavelength range from 2.5 to 12 μm, is designed and fabricated successfully. According to the electrically controlled birefringence characteristics of nematic LC molecules, the refractive index of LC materials filled into a prefabricated microcavity can be adjusted by the spatial electric field stimulated between the top aluminum electrode patterned by conventional UV-photolithography and the bottom aluminum electrode in the LC-FP. The particular functions including key spectral selection and spectral adjustment, can be performed by the developed LC-FP filter driven and controlled electrically. Our experiments show that the maximum transmittance of the transmission peaks is ~24% and the peaks of transmission spectrum shift through applying different voltage signals with a root mean square (RMS) value ranging from 0 to ~21.7Vrms. The experimental results are consistent with the simulation according to the model constructed by us. As a 4-channel array-type IR filter, the top electrode of the device is composed of four same sub-electrodes, which is powered, respectively, to select desired transmission spectrum. Each of the units in the device is operated separately and synchronously, which means that spectral images of the same object can be obtained with different wavelengths in one shot. Without any mechanical parts, the developed LC-FP filter exhibits several advantages including ultra-small size, low cost, high reliability, high spectral selectivity, and compact integration.