Abstract: Based on the diffusion transportation theory of chloride ion in concrete, the differential diffusion transportation equations have been proposed. The boundary and initial conditions of concrete members exposed to chloride ion environment are discussed. According to the mass conservation theorem in any finite control volumes of concrete, the differential equations of diffusion transportation can be derived as discrete equations. Matrix solution methods are designed for this Finite Volume Method (FVM). Examples calculation shows that the FVM is a good numerical analysis method for diffusion transportation simulation in concrete. This method can be used to analyze the chloride ion profile in concrete with arbitrary boundary conditions, and to predict the service life of concrete structural members exposed to chloride ion environment.