Pipeline fan convenient for adjusting air pressure

The utility model discloses a pipeline fan with air pressure convenient to adjust. The pipeline fan comprises a fan body, a first air pipe, an air guide pipe and a second air pipe. The air guide pipecomprises an inserting part; and an air guide part, the inserting part and the air guide part are coaxially and integrally formed; limiting protrusions are evenly distributed on the circumference of the inner wall of a cavity of an air inlet of the draught fan. The outer peripheral surface of one port, far away from the air guide part, of the air guide pipe is tightly attached to the inner wall ofa cavity of an air inlet of the fan; the end face of one end opening, away from the air guide part, of the air guide pipe abuts against the limiting protrusion, the end face of one end opening, awayfrom the inserting part, of the air guide pipe abuts against the air guide piece, and the inner diameter of a pipe opening of the air guide part is smaller than that of a pipe opening of the insertingpart. By means of the struc