Because of the mechanical situation, aerial carrier condition, environment condition and usage maintenance of the aerial camera, faults always occur. So it is necessary to check and maintain the aerial camera on the ground, and the interior structure of the aerial camera is very complex, and the aerial camera is composed by many circuit boards, and the checking must be performed from the whole camera to each component. Aiming at the demands of aerial camera fault diagnosis, the board level fault diagnosis system of aerial camera was developed in the article. The failure mode of the exposure board in the aerial camera electric control system was completely analyzed, and the exposure board fault board model based on Petri net was established, and the dynamical transition of the system status was solved by the relational matrix method, and the TPS program of the exposure board was compiled, and the fault diagnosis of the exposure board was primarily actualized in the article.