Abstract: In the context of harbor-shipping company cooperation, collusion could be the issue which should be prevented.Discrete time period infinitely repeated game model is constructed to study the possibility of vertical integration-horizontal collusion coexisting and the interaction between them.The research shows that, in the situation of severe market competition and only few shipping services options available, the vertical integration of shipping companies will eliminate the influence of horizontal collusion on shipping price.However, from the perspective of long-term game, vertical integration of shipping companies will make horizontal collusion more stable.