To analyze the behavior characteristics and trends of port’s collecting and dispatching system,we defined the concept of coordinated development of port’s collecting and dispatching system based on the synergetic and other theories. Taking Guangxi Beibu -gulf port as the research object, we present a system dynamics approach based on the system analysis and cause-and-effect analysis. The proposed SD model comprises 4 sub-modules: port throughout demand, throughout capacity, transport structure, freight structure. The basic simulation and policy simulation are carried out after the validation of the SD model, which can offer a theoretical basis for establishing relevant policies.