Abstract: A wind turbine generator, comprising a nacelle having a rear casing and a empennage member. When the generator is facing a stronger wind, the pivot joint which pivotally installed in the skewed chute will drive the connected tail pipework to deflect automatically, and further drive the rotation seat and the nacelle which installed above the seat to rotate simultaneously. When the speed of the wind slows down, the pivot joint which is installed in the skewed chute will return to the normal position due to the inertial force, so as the nacelle will back to the normal position as well. In light of the structural description stated above, an overloaded burning of the windings of the generator which caused by the strong wind can be avoided, and a possibility of deformation or damage to the blades and the stationary tower can be reduced.