A method,which is based on both experience and theory,to predict and analyze pump performance is presented.Individual losses in centrifugal pumps are analyzed and calculated,fully utilizing velocity triangles at the impeller inlet and outlet to describe flow conditions through the pump. The method presented here can quickly show the effect of individual parameters on pump performance.With few input variables,easiness to program and quick calculation speed,it can predict performance of pumps under both designed and offdesigned modes.