Abstract: Combined with high-power marine gearbox GW series ultrasonic testing case of large forgings, considering different parts of forgings and the operation force as well as different situations of defect hazards, this paper is to develop appropriate quality acceptance level to solve the too low pass rate problems of rough forging in production. Useful exploration aims to the rational use of materials for GW series of high-power marine gearbox in the production, and the feasibility of the method is proven.