Abstract: The system response of Fabry-Perot interferometer (FPI) imaging system to night airglow is discussed. The method to build the mathematical model of the interferometric system is described and the result is given. On this basis, the principle of measuring atmospheric temperature by FPI is elaborated. In addition, based on the analysis of the interferograms from a stabilized He-Ne laser, the system transfer function is derived and the discussion on the transformation of system transfer function at different wavelengths is also performed. The result from analyzing the images indicates that the analytical model and the method of wavelength transformation can be used to express the properties of the interferometric imaging system. The application of system transfer function in measuring night airglow, the temperature shift and the error estimation of the system are also briefly discussed.