Abstract: Simulation is one of the important means in obtaining distribution of atomic oxygen (AO) flux on spacecraft surface. In this paper, the basic characteristics of in-house software Atomic Oxygen Flux Software (AOFS) for AO flux calculation of spacecraft with complex geometry was demonstrated. The typical test cases of no-shielding, with-shielding, and multiple reflections for interactions between AO and spacecraft surface to verify software AOFS were proposed. The calculation results were compared with those of free molecular flow theory and software SYSTEMA. It is found that for no-shielding and with-shielding test cases, the software SYSTEMA using reverse ray-tracing method has better stability than software AOFS. For multiple reflections test case, the results of AOFS are not consistent with the results of SYSTEMA. The proposed study may provide a reference for the development and verification of software for calculating AO flux for spacecraft with complex geometry.