Abstract: In order to study the reliability method for durability design and service life prediction of marine concrete structures, a semi empirical and semi theoretical analytical model for durability design and service life prediction of marine concrete structures is analyzed, and the influence of geometric shape and section on the diffusion transportation of chloride ions in concrete is discussed. A new approach to durability reliability analysis is proposed in this paper. The method is called the FVM-MC simulation method. The principle of the method is to first calculate the chloride ion content in concrete structural members using FVM, then analyze the durability failure probability using a Monte Carlo simulation. Verification shows that the FVM-MC method is accurate and feasible, and it is a reliable method for conducting durability reliability analysis of marine concrete structures. Simulations show that geometric shape and section have significant influences on the durability and reliability of concrete structures. The risk of durability failure may be increased in concrete structural members with rectangular sections designed by the analytical Fick’s 2nd law model, because the impact of geometric shape and section has been neglected. Within circular sections, the diffusion transportation of chloride ions is similar to one dimensional transportation. Members with circular sections are conducive to durability.