In order to provide better guidance for the decision-making and cost optimization of LNG (Liquefied Natural Gas) tank container multimodal transport routes, with the objective of minimizing transportation costs, a mathematical model for optimizing LNG tank container multimodal transport routes based on transshipment terminals has been constructed. The study investigates a three-tier multimodal transport network comprising LNG receiving terminals, transshipment terminals, and customers. Employing a two-stage approach, the first stage addresses the overall transportation route planning problem based on transshipment terminals, while the second stage, building upon the results of the first stage, deals with the optimization of multimodal transport modes. Through the utilization of the GAMS programming language and the CPLEX and DICOPT solvers, the model was subjected to case study analysis. The results revealed that, in comparison to the traditional point-to-point direct transportation mode, the combination of transshipment terminals and multimodal transport can significantly reduce transportation costs. Additionally, sensitivity analysis was performed on the capacity of transshipment terminals and discount coefficients, highlighting that variations in discount coefficients and capacity have a direct impact on the choice of transportation modes, transportation route selection, and overall transportation costs. The case studies have validated the effectiveness and feasibility of the transportation model proposed in this paper. Adoption of the transportation model presented in this paper is expected to substantially reduce transportation costs and can serve as a valuable reference for LNG supply enterprises.