Crack is the defect that is serious and unavoidable with respect to concrete, greatly affects physicomechanical properties, lifetime, durability of concrete and reinforced concrete structures. Especially, with concrete and reinforced concrete structure used for seaside protection, the occurrence of cracks is the place where chloride and sulfate ion can easily penetrate inside, then speed up the corrosion process, thus cause lower strength, durability and lifetime of work The cracks can be limited if causes is considered and preventive measures is used reasonable. It will help manufacturer make high quality concrete product, increase durability and lifetime of works. This paper discusses the causes of cracks and measures to limit the crack for concrete and reinforced concrete in general and concrete used for seaside protection in particular.