The influence of stress level on the diffusion rules of chloride through maritime high-performance con-crete in splash zone was investigated under constant flexural load，and the load-affected microstructure of the con-crete and the hardened paste was also analyzed by means of SEM-EDS and BET tests． The results show that (1) in the pure bending section，the content of chloride in the concrete at a given depth increases with the increase of the flexural load; (2) for typical maritime high-performance concrete mix，there is approximately an exponential corre-lation between the flexural load and the constant load factor，so that the influence of flexural load on chloride diffu-sion coefficient should be considered in the durability design of concrete structures; (3) the increase in flexural load not only widens the micro-cracks in the interfacial transition zone but also improves the proportion of capillary and macro pores in the hardened paste，and eventually results in the increase of the total pore volume and average pore size，thus decreasing the resistance of concrete to chloride ion penetration．