In order to study the aerodynamic interference and movement rules of external store, computational fluid dynamics (CFD) methods were used to simulate the release process of airborne buoy in R/S UAV. A Moving-embedded grid approach is used coupled with an unsteady N-S equations, and a 6-DOF kinetic equations is fully integrated into the CFD solution procedure to capture the time-dependent interference between the stationary and moving boundaries. All major parameters, such as displacement, angular orientations and force, and their change trends were obtained. The results show that free separation of buoy cover could have a significant impact on the safety of UAV during the release process of airborne buoy. Consider the state of the buoy cover attached to the buoy parachute, the closest range of buoy from the propeller is 0.151m when the initial speed is 0.0 m/s, the safety margin is not enough; however, the closest range of buoy from the propeller is 0.671m when the initial speed is 1.8 m/s, the safety margin is enough.