Multimodal transport is an effective organization for the efficient transportation of goods. The choice of routes is mainly affected by transportation costs and time. Therefore, it is necessary to consider these three factors. In this paper, the transportation multi-modal transport system optimization model is constructed with the aim of transportation cost and transit cost. The Yibin Port-Shanghai Port is used as the research object, and the model is solved by the depth-first search algorithm. The results show that when the quantity of goods is less than 500t, the transit cost of goods is the smallest in Hefei Port. When the quantity of goods exceeds 500t, the transit cost is the lowest in Jiujiang Port. The study will help relevant personnel to provide a reference for the development of multimodal transport promotion policies.