In order to evaluate the environment corrosion and to analyze the anticorrosion capacity of the secondary lining of subsea tunnels, a series of researches based on both technical codes and indoor accelerated corrosion tests are carried out. The result shows that the corrosion grade of the exterior side of the secondary lining of Xiang’an tunnel in Xiamen is Grade D, and that of the interior side of the secondary lining of Xiang’an tunnel is grade E. The results have been applied in the design of Xiang’an tunnel. Both Type A mixing proportion (water/binder ratio of 0.36, 60% of slag powder) and type B mixing proportion (water/binder ratio of 0.36, 15% of fly ash and 60% of slag powder) can meet the strength requirement of C45 concrete and can achieve good anticorrosion capacity, therefore they are recommended for Xiang’an tunnel. In the end, Type B mixing proportion is adopted for the concrete of the secondary lining of Xiang’an tunnel.