Abstract: Provided is a blade capable of efficiently utilizing low-velocity fluid. The blade includes a main wing component, the main wing component has a streamlined cross section, an outer profile of which forms a first airfoil, the blade further includes a head wing piece in form of a sheet, the head wing piece has an arc-shaped cross section with a convex surface at one side and a concave surface at the other side, the head wing piece is arranged obliquely above a leading-edge point of the main wing component with the concave surface of the head wing piece facing the main wing component and a first ventilation space is formed between the head wing piece and the main wing component. By improving the configuration of the wing pieces of the blade, Cp of the blade is improved, and the manufacture cost of the blade can be significantly reduced.