Because the slope protection and foot protection of breakwater are filled with large size stone，it is difficult to set the spiral pipe of the conventional water operation platform of cast-in-place pile，which makes it difficult to form the platform foundation system. According to the series of problems in the original design scheme of the steel platform，we carry out the optimization design，and finally adopt the foundation support system of the shore side backfilling block stone and 2 rows of beret frame and 1 row of spiral pipe piles. The results show that the stress and bearing capacity of the platform foundation system are qualified，the steel platform does not have a large slip mutation during the construction of the cast-in-place pile，and the settlement is relatively uniform. The water work platform is safe，reliable and convenient for construction.