: In this paper, numerical simulation and experimental technologies are used for the study of atomization and differences of swirl atomizers, which supplying with aviation kerosene and diesel oil. Different geometry parameters are analyzed to investigate their influence on the atomization. And the internal flow field is also revealed through this study. The main contents and conclusions of this study are as follows: there is deviation between numerical simulation and experiments, but the trend of spray cone angle and discharge coefficient varying with pressure presents highly conformity, which verifies that using the fluid volume function (VOF) to track the oil and gas two phase interface is properly for the study. The vortices in the liquid phase and gas phase are the motive for instable flow, which also leading to the waves on the liquid sheet. Geometry parameters make a big difference on the atomization. After optimizing the structure of the nozzle, the flow coefficient and the spray cone angle increased by 0.15 times, and 0.16 times, respectively, and the liquid film thickness decreased by 0.53 times, which obviously improves the atomization quality of the nozzle.