Aiming at the maintenance of large ship locks in mountainous rivers，the maintenance gates types and lifting equipment are compared from the aspects of investment cost-effectiveness，commonality，convenience，etc.，therefore，it is determined that the maintenance plan of Qianwei ship lock is“floating stacked beam maintenance door + crane ship”. The particularity of Qianwei ship lock maintenance is described in detail，and the research on the hoisting process of the crane ship in Qianwei ship lock maintenance is carried out. Through experience summary and boundary condition simulation methods，the key control elements of crane ship in hoisting super large floating stacked beam maintenance door are obtained. The article introduces in detail the application of crane ships in the lifting and maintenance of gates in large ship locks in mountainous rivers，which provides experience and reference for similar large ship locks.