The ionospheric characteristics such as total electron content and plasma bubble parameters can be retrieved by observing the ionospheric airglow with spaceborne imager. Atoms and molecules absorb solar radiation and excite to higher energy states in the daytime. At night, they radiate the energy in the form of airglow. The radiation intensity is related to the density of ionospheric components. Therefore, airglow is an excellent tracer for observing the ionosphere. In order to promote and optimize the design of space-borne imager and enrich the ionospheric detection methods, it is necessary to conduct imaging simulation analysis of global airglow. The main works of this paper are as follows: (1) the photochemical reaction process of 630 nm radiation at night is analyzed, and a simulation analysis method of airglow imaging is designed. The intensity distributions of airglow in four different seasons with high and low solar activity are obtained, which provide a theoretical basis for setting detection index; (2) the simulation research of space-borne imaging is carried out, including imaging chain and signal-to-noise ratio analysis. A typical imager parameter with a time-delay integral imaging method is used to carry out the simulation combined with the satellite orbit. The main conclusions are as follows: (1) the intensity of 630 nm at night is closely related to the solar radiation intensity in the daytime. The average night radiation intensity with high solar activity is 115 Rayleigh, and that with low solar activity is 50 Rayleigh, the radiation intensity and distribution are consistent with the actual observation results of GLO-1 and ISS-IMAP; (2) the observation width and horizontal resolution of typical parameter imager reach 245 km and 1 km. The signal-to-noise ratio is more significant than 10 for the intensity greater than 50 Rayleigh, it means the typical parameter imager can observe the global structure of ionospheric airglow with high solar activity. The research results in this paper provide a theoretical basis for space-borne ionospheric airglow detection and provide a reference for observing other wavelengths.