Abstract: Navigation tunnels are regarded as one of the effective ways to solve the layout problem of navigation buildings under the conditions of high mountains and valleys, and their section design is restricted by several factors. An objective optimization mathematical model for cross-sectional dimensions of large navigation tunnels is established in this study based on design passing capacity of navigation tunnels and critical ship speed. Section coefficients of navigation tunnels and tunnel widths are adopted as objective functions, while design passing capacity and critical ship speed are adopted as the constraints of the proposed model. And then, the multi-objective optimization problem of the proposed model can be transformed into a single-objective optimization problem according to the actual situation of engineering projects, and optimal solutions of objective functions can be solved based on the constraints. The proposed model is applied to the cross-sectional dimension analysis of the Goupitan navigation tunnel. The calculation results are in good agreement with the actual project, which verifies the rationality and effectiveness of the model.