Due to the coupling of cavity, cavity wall and embedded object, the flow in the cavity is complex and has a strong unsteady flow characteristics, which makes the interior object has a complex force during the process of object delivery and seriously affects the safety. In this paper, computational fluid dynamics (CFD) method, coupled with six-degree-of-freedom equations are used to simulate the separation process of embedded object. The effects of different flow Mach numbers on the trajectory and attitude of the embedded object. According to the analysis results, the flow control measures were designed, and the jet control was added to the front of the cavity and the pressure relief tube was installed at the bottom of the cavity. The results show that the shear strength of the cavity opening is different when the Mach number is different; with the increase of Mach number, the pressure in the cavity is more uneven along the flow direction, the aerodynamic force of the interior object increases, the attitude of the interior object tends to be unstable, the change is more intense, and the angle of pitch up is larger. After the installation of the leading edge jet, the flow near the shear layer is effected, the pressure gradient near the shear layer is reduced, and the velocity of the object obviously increases when passing through the shear layer. The pitch angle and yaw angle decrease. As the jet strength increases, the more stable the attitude changes. The pressure distribution in the cavity tends to be uniform after the pressure relief tube is added to the bottom of the cavity, which is helpful to improve the trajectory of the embedded object.