The invention relates to the field of optical detection, in particular to a method for simultaneously detecting atmosphere of an edge and a substellar point of the earth by utilizing an omnidirectional imaging system. The method comprises the following steps of: reflecting or refracting light rays through an N-pyramid reflector in the omnidirectional imaging system; and forming annular light spots and circular light spots of ultraviolet band light rays on an optical imaging unit in the omnidirectional imaging system under the filtration of a narrow-band filter. The atmosphere of the edge and the substellar point of the earth is simultaneously detected spatially by the omnidirectional imaging system, the atmosphere is subjected to wide-range high-resolution detection in the ultraviolet band, and accurate omnidirectional and multi-space-time atmosphere information is provided.