Volute of axial-flow fan

The utility model discloses a volute of an axial-flow fan. The volute comprises an arc-shaped cover plate, an upper cover plate and a lower cover plate, wherein the upper cover plate and the lower cover plate are arranged at the two sides of the arc-shaped cover plate; the upper cover plate is provided with an air inlet; the lower cover plate is provided with a motor fixing hole; the arc-shaped cover plate is provided with an air outlet; a circle of groove is y arranged at each periphery of the two sides of the arc-shaped cover plate; a circle of boss matched with the groove is arranged at each periphery of the upper cover plate and the lower cover plate; and a flange is arranged on the air outlet of the arc-shaped cover plate. The volute disclosed by the utility model has the advantages of simple structure, convenience in installation and cleaning, detachability, and low manufacturing cost.