The invention discloses the manufacturing theory of an internal thrust external spraying low impedance water flow generator impeller, belonging to the technical field of hydraulic power generation and processing utilization and being characterized in that a plurality of blades which can horizontally swing between limited posts are arranged between two rotary tables to be made into an impeller, and then a channel which infuses water flow into the interior of the impeller is opened by using water flow which flows into the interior of the impeller from the exterior of the impeller along the flow direction and changes the swinging angle of the impeller to cause that the interior of the impeller concentrates very strong water pressure, from which the internal thrust on the blades generated by the water flow or ocean wave and the reacting force on the blades formed by water flow external spraying are obtained to push the impeller to drive the generator to operate, thus realizing efficiently turning the water flow or ocean wave into electrical energy. The manufacturing theory has advance and innovation of effectively increasing the efficiency of using water flow to generate power and providing feasibility technical support for manufacturing small and medium sized and more than tera-scale water flow or ocean wave electric generating sets with high efficiency.