Individual-soldier firepower system includes several subsystems, and the relationships of competition and coupling exist in each subsystem. In order to obtain the optimal performance of the entire system, the multidisciplinary optimization is employed in this paper. The recoil force is taken as the objective function, and the performances of weapon dynamics, internal ballistics, external ballistics and terminal effects are taken as the subsystems. To establish the multidisciplinary optimization model of individual-soldier firepower system, the collaborative optimization method is adopted. And then, for optimizing the complicated system globally, the parallel, global and local optimization methods, response surface methodology, and subsystem models are used to carry out the optimization computation on the basis of considering the coupling relationships of each sub-discipline. The computational results shown that, the multidisciplinary optimization of individual-soldier firepower system can not only ensure the performances of internal ballistics, external ballistics and terminal ballistics, but also further optimize the recoil force.