Corrosion is a major concern for the durability of concrete structures under marine environment. In this paper three series of concrete was immerged in sea water to reseaech its development of compressive strength, microstructure and corrsosion production. The results showed that compressive strength of controlled concrete was decreased but it can further increased added fly ash and silicon fume after immerged in sea water. It can be observation by SEM and EDS that a number of complex salt was produced on the surface and AFt was produced inside controlled concrete. It can produce expand and lead to cracks. As result of fly ash and silicon fume added, the crystals of Mg(OH)2 was formed on the surface and no crystal and cracks was produced internal concrete. The compressive strength can still increase after immerged in sea water.