Abstract The design of narrow-passage centrifugal impeller (Q=0.5 m~3 /h) is introd uced in this paper, this kind of impeller, with smaller flow capacity and higher delivery lift, is design by blockading a part of the flow passage. The design i ncludes: to block a part of the flow passage and to enlarge the outlet impeller width (b 2), resulting in easy manufacture and controlling the flow capaci ty and reducing the hydraulic loss in the flow passage. The test indicates: the hydraulic design part is successful because it can meet the need of the pump wit h a flat performance curve. This kind of impeller can be widely used with smooth operation. Also the physical dimension can be easily guaranteed during the manu facturing procedure.