•The effect of concrete crack on chloride transmission was investigated by ABAQUS.•The macro/meso-scale simulation model were used to simulate the chloride migration.•The developed meso-scale model was used to simulate the transmission behavior. The influence of cracks with different widths on chloride transmission has been investigated by experimental tests using the method of rapid chloride migration (RCM) and numerical simulation using finite element analysis with software ABAQUS. Meso-scale finite element simulation model has been developed to study the aggregate heterogeneity. It is found that numerical simulation results are in good agreement with the experimental measurements. When the crack width is less than 0.05mm, the influence of the crack can be ignored. While the crack with width is in the range from 0.08mm to 0.1mm, the dispersion accelerates with crack width increasing. When the crack width is larger than 0.1mm, the transmission of chloride is similar to the transmission in the liquid. The finite element method verified by the experimental results can be further applied to systemically explore the correlation of the behavior of chloride dispersion with specific crack width.