"Axial Fan" performance characteristics is flow, head (total pressure) is low, is greater than the number of revolutions, the axial fluid flows in and out of the impeller. Its structural features are: simple structure, relatively light weight. Due to a greater angle of rotor blade hub can be made adjustable. Moving blade adjustable "Axial Fan", since the moving blade angle can be changed with the external load changes, thus varying conditions regulating performance, maintained a wide and efficient work-space. Because of this there is no way around the ventilator impeller cover, the fluid flow in the impeller, similar to the aircraft flying wing with air. Therefore, the "Axial Fan" in the study of energy conversion relation between the blade and the fluid, using a wing theory. We can understand the airfoil, Cascades and its main geometric parameters.