Abstract: To analyze the gas interaction influence on the dynamic characteristics of the sub-munitions during the transonic separation of the cluster munitions, a three-dimensional dynamic model was built and the process of separation under the action of gas interference was simulated based on the experiment tests at the three-typical separation Mach numbers:0.8Ma, 1.2Ma, 3.0Ma. The dynamic characteristics of the sub-munitions caused by the gas interference were analyzed. And a boundary grid adaptive method was used to improve the separation feature. The results show that the gas interference mainly exists in the initial separation phase. With the increase of the separation Mach number, the effect of the gas interference becomes weaker under the influence of the flow field and shock wave. The existence of the gas interference has a certain influence for the angular velocity. The initial disturbance time is 12, 10, 5ms which makes the angular velocity value increased by 54%、97%、3% respectively.