The invention discloses a wind power variable pitch drive system, and particularly relates to an electric direct-driven wind power variable pitch drive system which is high in reliability, low in cost, high in efficiency and little in occupied space. The system comprises a hub, a variable pitch bearing outer ring and a variable pitch bearing inner ring, wherein the variable pitch bearing outer ring is arranged on the hub, and the variable pitch bearing inner ring is matched with the variable pitch bearing outer ring in a rotating mode. The system further comprises a linear drive mechanism which is rotatably installed on the circumferential edge of the variable pitch bearing inner ring, and one end of the linear drive mechanism is provided with a joint bearing which is hinged to the hub. Linear motions provided by the linear drive mechanism are directly transferred into rotation of the variable pitch bearing inner ring, a complex transmission structure is avoided, and accordingly the occupied space of the whole mechanism is substantially reduced, the whole mechanism is completely in the hub, holes do not need to be formed in the hub, rigidity of the hub is improved, and the system has the advantages of being low in weight, simple in structure, high in reliability, long in service life and the like.