In the process of multi-body separation of sub-mother UAV, the analysis of aerodynamic interference characteristics is an important research direction in swarm UAV launch technology. In this paper, based on the dynamic nested unstructured polyhedral mesh technology, the unsteady N-S equation of the flow field and the six-degree-of-freedom motion equation of the rigid body are coupled to realize the accurate simulation of the multi-body separation process of the sub-mother UAV. Firstly, the aerodynamic interference zone of the parent UAV and the separation mode of the child UAV are analyzed. Secondly, the aerodynamic interference characteristics of the sub-mother UAV and between the sub-UAV and the sub-UAV and the sub-UAV in the overall state are calculated. Finally, according to the change of the motion state of the sub-UAV in the process of multi-body separation, the safety characteristics were evaluated. The results show that compared with deceleration separation, accelerated separation can get out of the aerodynamic interference region faster and has higher safety. Moreover, with the increase of the number of sub-UAVs, the distance of the wings of the sub-UAV decreases continuously, and this also weakens the influence of the wingtip vortex on the wing surface of the sub-UAV to a certain extent and increases the lift of the sub-UAV.