Aiming at the problem of the 3，500 m3/h cutter suction dredgers changing flow rates with pipe nozzles under the condition of short-distance pipeline delivery，we carry out research on the optimization of inboard pumps and impeller blades of submerged pumps to reduce the head and power of dredging pumps，and apply the modified impeller in the dredging construction project of Haimen in Nantong.The results show that replaced with the new impeller for the dredging pump，the Xinhailu dredger can use double pumps in series to transport silt soil mud.The power of two dredging pumps drops about 500 kW，which can save 13.4% of fuel consumption（saving 30 t fuel in 180 h of construction）of the dredger and achieve energy conservation.