The invention discloses a medium and small sized variable propeller pitch wind-driven generator, which mainly comprises a generator, a hub, a rotating body, a bearing chamber and a vertical shaft. The front end of the generator is connected with the hub through a spindle; a hub cover is arranged on the hub; the rear end of the generator is fixedly connected with the rotating body; and the bottom of the rotating body is connected with the vertical shaft through the bearing chamber. The wind-driven generator is characterized in that: fan blade connecting shafts are uniformly distributed on the hub annularly; centrifugal hammers are arranged on the fan blade connecting shafts; the fan blade connecting shafts are arranged at one end in the hub to be connected with a synchronous mechanism; the synchronous mechanism is connected with a synchronous disc which is arranged at one end of a reciprocating rod; an offsetting spring is arranged between the synchronous disc and the hub cover; the reciprocating rod passes through the spindle to extend into the rotating body; the reciprocating rod and the spindle are in movable fit; a poking arm is connected in the rotating body through a brake bracket hinge; one end of the poking arm is contacted with the reciprocating rod, and the other end of the poking arm is connected with a brake rod; and the brake rod passes through the bearing chamber to extend into the vertical shaft.