Large-scale missiles are generally catapulted by the ejector. And a tail cover is used to protect the first stage rocket engine. When the missile reaches the predetermined height, the tail cover should be separated timely so that the engine can work properly. In this paper, a braked tail cover separation concept is proposed. And a new type of tail cover separation device is designed according to the concept. Firstly, the forces analysis and the internal ballistic simulation of ejection are conducted before setting working conditions. And then, the finite element software Abaqus is adopted to achieve the simulation of tail cover separation process. Through analyzing the obtained results, it’s concluded that the braked tail cover separation concept is feasible. Moreover, the influence of material changes on the braking effects is also studied.