In order to obtain the chloride ion transport law in reinforced concrete structures under dry and wet alternating effects. Considering the blocking effect of steel reinforcement, a model of chloride ion convective transport in reinforced concrete structures under dry-wet alternation is established, the applicability of the model is verified through experiments, and the parameters are analyzed based on two-dimensional meso-concrete model. The results show that the blocking effect of steel reinforcement causes chloride ions to accumulate on the surface of concrete and increase with the increase of dry-wet alternation time. In the mesoscopic model, with the accumulation of chloride ions in concrete, the peak value and location of chloride ion content appear in the surface layer. The chloride ion content was larger in reinforced concrete structures compared to plain concrete, and the chloride ion content was positively correlated with the increase in reinforcement diameter. The increase in the dry-to-wet time ratio accelerated the transport of chloride ions within the concrete, and the lower the initial solution saturation is, the higher the chloride ion content is, When the initial saturation is 0.1, the peak chloride ion content is 0.605%.