The invention discloses a supporting device of an axial flow fan. The supporting device comprises an air barrel. The supporting device is characterized in that supporting pipes, motor installing flanges and a surrounding plate are arranged in the air barrel, the motor installing flanges are located in the center of the air barrel, the peripheries of the motor installing flanges are fixedly connected with the surrounding plate, the supporting pipes are arrayed on the outer circumference of the surrounding plate, one end of each supporting pipe is fixedly connected with the surrounding plate, and the other end of each supporting pipe is fixedly connected with the inner wall of the air barrel; and the supporting pipes gradually downwards incline in the horizontal direction from the ends of the motor installing flanges to the end of the air barrel, the bolt connecting strength on the motor installing flanges is greatly improved, resonance, generated during running, of the whole machine is avoided, and the balance of a rotation piece of the whole machine is guaranteed.