For the leaching damage of seawater coral aggregate concrete caused by salt spray effect in the tropical marine environment, research of carol aggregate concrete structures in South China Sea was conducted. The physical and mechanical properties, micro pore structure deterioration analysis were carried out. The results show that serious erosion damage exists on the coral aggregate concrete protective layer exposed to salt spray environment. The little pores are transformed into larger harmful pores and the porosity increased obviously, which leads to harsh decrease in the quality、strength properties of the concrete. It is also found that the cementious structure of coral aggregate concrete is seriously damaged. The loss of C S H and Ca(OH)2 is serious, and the non cementation products like Mg(OH)2 increases. This investigation result is of important scientific guidance for the design of construction technology of coral aggregate concrete，as well as for its long term operation and maintenance.