Three optimization objectives are proposed to suppress transition during the armature launching process: the deviation rate of the current density distribution on the armature rail’s contact surface under steady-state current, the deviation rate of the current density distribution on the throat’s surface under steady-state current, and the deviation degree of the overfill contact pressure’s center of action. The NSGA-2 multi-objective optimization algorithm is used to optimize the armature structure. Firstly, the random response surface of the optimization objectives is established in a large range of armature geometrical parameters, and then the range of values of armature geometrical parameters is obtained according to the limitations of the armature structure in the actual problem, and then the optimization of the armature structure is carried out and the optimal compromise solution is screened out in this range. The simulation results show that the optimized armature, compared with the benchmark armature, has a more centered distribution of the overfill contact pressure on the contact surface, smaller current peaks on the contact surface of the armature rails during the launching process, and lower maximum temperature at the throat, which indicates that the optimized armature is more capable of suppressing the armature start-up phase transition, the magnetic saw of the throat transition, and the current falling-edge phase transition.