The invention relates to a mixing and stirring system utilizing wind energy for anaerobic sewage treatment. The system is formed by connecting a wind energy conversion mechanism with a wind energy transmission and stirring system by a fixing device, wherein air wings in the wind energy conversion mechanism are fixed on hubs, one end provided with a horizontal transmission shaft is in running fit with the hubs, the other end is coaxially connected with a speed reducer input shaft on a speed reducer body by a coupler, and the speed reducer body and an engine room casing arranged on the outer side of the speed reducer body are respectively fixed on supporting plates; the system is provided with a yaw bearing, a yaw drive and a yaw brake, which are respectively fixed on the bottoms of the supporting plates, and the speed reducer body is provided with a speed reducer output shaft; and the top of a vertical transmission shaft in the wind energy transmission and stirring system is connected with the speed reducer output shaft in the wind energy conversion mechanism by a coupler, and the bottom of the vertical transmission shaft is connected with a stirring paddle. The invention utilizes the wind energy to drive the stirring paddle of the system to rotate in an anaerobic sewage treatment tank, improves the efficiency of anaerobic biochemical reaction, and has the advantages of reasonable structure, convenient application, energy conservation and high efficiency.