The invention discloses a manufacture method of an offshore riprap leveling ship. The manufacture method comprises the following steps of: firstly, preparing for works; preparing for materials, to be specific, manufacturing a ship body by sections, manufacturing an iron outfitting and a piping system, manufacturing pile legs, a lifting mechanism, a big vehicle infield and a small vehicle infield; preassembling, carrying out sand washing and coating, largely combining by sections after sand washing and coating, installing a deck machine and the lifting mechanism; carrying out combining pipe installation, internal decoration and cabin tightness test; coating finish after the large combination by sections, the lifting mechanism installation, the combining pipe installation, the internal decoration and the cabin tightness test are completed; and finally, installing a big vehicle and a small vehicle to form the ship body, launching the ship body, debugging the ship body after launching, installing and debugging the pile legs, installing and debugging a belt conveyor and a riprap device on the ship body after the ship body and the pile legs are debugged, then carrying out inclination test, and finally delivering the ship. The manufacture method has the advantages of reducing construction procedures, lowering production cost and increasing production efficiency.