Abstract: Allocating properly the system specification plays an important role in the satellite system design.In the paper,satellite system design specification including error,mass,power and reliability are optimally allocated with nonlinear optimization and Multiobjective and Multidisciplinary Design Optimization (MMDO).The result shows that the optimization models and the optimization methods,nonlinear optimization and multiobjective and multidisciplinary design optimization,are both feasible and effective.