Considering the karst geological conditions and groundwater erosion environment of Hejiangtao tunnel, the durability of reinforced concrete structure of the tunnel was analyzed using COMSOL-Multiphysics software, and the corresponding durability protection measures were then formulated. The results show that there is corrosion risk of segment structure, and different corrosion forms will be caused by the change of initial porosity. The segment is effectively prevented, avoiding to contact with groundwater, using the designed measures of silane coating and waterproof rubber sealing. Consequently, the durability can be improved.