The concrete pipe pile is likely to be damaged to form circular or vertical cracks during construction and operation due to its concrete structure.Such cracks mainly occur within water level fluctuation area and above,also underwater even under the mud level.The above-water maintenance and strengthening technique is unable to be directly applied to the underwater construction due to the restriction of technology and construction conditions.Combining with wharf engineering cases,we propose the technology of applying the steel casing outside the pipe pile and then concreting to form similar steel casing concrete pipe pile structure for the maintenance and strengthening of the cracks.