Abstract: Systems dynamics provides theories and approaches to explore complex systems. However, the optimization in a systems dynamics model still follows the "try-and-error" method, which does not work satisfactorily. According to the principles of systems dynamics, the paper proposes a general formulation for the policy optimization problem in a systems dynamics model by introducing a control policy function. Combining with genetic algorithms, , the order policy optimization in a distribution and super-market system is addressed. This paper aims to develop basic principles of systems dynamics and discuss the control and policy optimization for social economic systems.