Under the background of carbon peaking and carbon neutrality, the low-carbon transformation of multimodal transport has attracted much attention.In view of the exploration of transportation route optimization by the transportation industry, this paper comprehensively considers transportation cost, carbon emission and other factors. At the same time, the carbon tax policy is added to establish a low-carbon multimodal transport path optimization model with the total cost of goods transportation and the lowest carbon emissions as the goal, and combined with the case through the genetic algorithm to calculate the optimal low carbon multimodal transport combination mode and path. The research results show that this model can optimize the transportation structure, productively decrease transportation costs and carbon emissions, and reasonable carbon tax policy can provide freight enterprises with transportation mode and path decision guidance, to achieve efficient low carbon transportation, and further facilitate the sustainable progress of society.