Abstract: Aim To study the optimum method of designing reentry vehicle systems., Methods The method of step acceleration and sequential unconstrained minimization technique were used to minimize the mass of reentry vehicle and get the optimum plan. Results and Conclusion The calculated ballistic data were consistent with those ofthe true flying trajectory,and the optimized parameters were more rational than the original, which made the mass of the vehicle smallest. Al of this show that the theory and the calculating method herein can be used in the phase of the program design of the system design of reentry vehicles.