The invention relates to a low noise axial fan with rotating flow guide ring, comprising electric machine, vane, machine casing, bracket and wheel hub, where the wheel hub is arranged at the lower part of the machine casing, the electric machine is arranged above the wheel hub and coaxially connected with the wheel hub and fixed on the inner surface of the machine casing, the section of the bracket is streamlined, the vane is of an integral fixed vane angle profile and of a forward-swept shape, wide outside and narrow inside, and these vanes are not equidistantly arranged, and the link line of gravity centers of various sections of the vane forms an included angle <=30 deg. with its radial straight line. The lower inlet end of the machine casing is provided with rotating flow guide ring rotating with the vanes, the upper cylinder body of the flow guide ring is integrated with the vane circumference, and keeps a rotating gap from the inner diameter of the machine casing, a bottom circular arc flow guide ring is of a 1/4 ellipse in shape, and the lower annular end surface of the machine casing is arranged in the flow guide ring and forms an axial gap from a platform in the flow guide ring to be good for relatively rotating. The invention has remarkable noise-reducing and energy-saving effects.