In order to study the effect of the irregularity of dry-wet cycles on chloride transmission in concrete cover under marine environment， comparative tests under continuous and discontinuous dry-wet cycles were carried out. The effect of water-cement ratio and dry-wet cycles regime under different dry-wet cycles on the distribution of chloride content in concrete cover and the change of choloride content in convection zone was studied. The results show that the chloride content has an inflection point in the convection zone due to the transmission phenomenon of bidirectional convection and diffusion when the time of dry-wet ratio（t_d/t_w） is relatively high. The depth of convection zone decreases as the mass of water-cement ratio decreases， while the peak chloride content increases with the reduction of t_d/t_w. Compared with continuous dry-wet cycles， the discontinuous dry-wet cycles have a significant effect on the variation of chloride content with the depth and the peak chloride content in the concrete cover.