Fabry–Pérot interferometer is a multi-beam interferometer, with the advantage of high spectral resolution, and can be used to research the fine structure of the matter. The application of Fabry–Pérot interferometer in spectral imaging instrument will improve the spectral resolution. And it can also enhance the structural efficiency and promote the miniaturization of the spectral imaging instrument, which makes it convenient to be used in aviation and space applications. Here, we propose a method of hyperspectral Imaging based on Tunable Fabry–Pérot interferometer. At first, the time-domain interferogram is obtained by adjusting the cavity length during shooting, then, the corresponding relationship between the interferogram and the spectral curve can be described by the theoretical model of multi-beam interference, and linear equations can be obtained by discretizing the theoretical model. Finally, the spectral curve can be obtained by solving the equations. Good results come out of the simulation of this method. It has high precision and spectral resolution.