The utility model provides a pump unit under sea water pump, includes: install base, the pin joint rotary platform on the base on the quayside, wherein, the rotary platform left -hand thread is on thebase, and rotary platform is last to be equipped with takeover, hoisting point and to be used for placing the cardboard to taking over for all apparatus are all put together, link together to takeover and sea water pump and flanged bend to integral erection is on rotary platform's assigned position, and carry out the testing of sea water pump through switch board control sea water pump. The utility model discloses not only easily the pipeline is deposited, has solved the problem that no department deposited, has improved work efficiency greatly, and, overturn through rotary platform for rotary platform stands on the sea sky, and easily cause the problem of friction damage near the pier when having avoided time pump, greatly reduced the on -the -spot construction degree of difficulty, thequality and the security of construction has improved.