To counter the contradiction of water navigation，power generation and agricultural water，the Feilaixia second-line and third-line locks were planned to be operated by water-saving mode during water filling and emptying.Hydraulic model experiments were carried out to study the characteristics of water-saving and the benefits.The water-saving ship locks of double lines were compared with the single lock，and the result showed that water-saving ship locks could save 2.89～3.77 million tons of water，and generate 13.5×106～17.5×106 kW?h of hydropower energy.Thus the conclusion is drawn that the water conditions of chamber and approach channel are more favorable，and the berthing conditions in the chamber are better.The ship locks of water-saving satisfy navigation requirements，and the water-saving ship locks will have remarkable economic and environmental benefits.