This paper introduces the concept and the basic principle of the 3-D flow technique, including the production of the 3-D flow theory, the equation expression and the solution of the 3-D flow equation, based on the actual operating condition of the water pump.The water pump impeller is designed, the impeller of the water pump is analyzed, and the selection of the impeller material of the sea pump is compared to the parameters before and after the transformation.The saving power is significant.