Abstract: Axial flow pumps are widely used in agricultural area because of their high flow rate and low head. Accurate prediction of boundary layer transitions is important to improve the accuracy of internal flow calculations in axial pumps. The applicability of the SST γ-Re_θt transition model at different Reynolds numbers was explored with a hydrofoil. It was found that the prediction accuracy of the SST γ-Re_θt transition model was close to the experimental value under the low Reynolds number condition（Re_L was less than 1.6×10~6）; under the high Reynolds number condition, the boundary layer transition position predicted by the SST γ-Re_θt transition model was gradually moved forward compared with the experimental value as the Reynolds number was increased. This indicated that the SST γ-Re_θt transition model was not effective in determining the occurrence of boundary layer transitions in high Reynolds number hydrofoils. Based on this, the transport equation in the SST γ-Re_θt transition model was modified by using the ambient source term method, introducing the parameters of environmental turbulent kinetic energy and environmental turbulent specific dissipation rate, and establishing the relationship between turbulent specific dissipation rate and Reynolds number to obtain the modified SST γ-Re_θt transition model. The model was validated in the high Reynolds number flow of Donaldson trailing edge hydrofoil and NACA0016 hydrofoil. The prediction accuracy of typical flow characteristics such as wake vortex shedding frequency under the condition of high Reynolds number of Donaldson modified trailing edge hydrofoil was improved by about 8% compared with the original transition model. Compared with the original transition model, the prediction accuracy of the relative thickness of the boundary layer and the coefficient of friction in the transition region in the middle of the hydrofoil of NACA0016 was improved by more than three times.