The invention discloses a homonymous differential centrifugation self-control gear stepless speed changer. The central shaft of the speed changer is an output shaft and is integrally concentric with a central gear; a gear reducer assembly and a gear ring wheel are concentrically rotated on the central shaft; an orientation wedge type clutch is used for locking the gear reducer assembly to rotate homonymously; the central gear is engaged with a reduction gear and is used for driving the reduction gear to decelerate until a final gear drives an inner gear ring to output high torque; a centrifugal wall pulley is rotated along with the gear ring wheel; a thrust valve is pulled by centrifugal force so as to be fixed in the reducer assembly; the flow of liquid oil in a liquid oil damping device is gradually changed from high to low, so that the rotational resistance of the reduction gear in a reducer is gradually changed from low the high, and the homonymous differentials of the central gear and the gear reducer assembly are gradually changed from high to low; therefore, the inner gear ring is driven by the rotation of the final gear until the inner gear ring is driven to rotate through the revolution of the final gear so as to form the stepless speed changer. The speed changer has high gear ratio, high mechanical strength and low mechanical friction; and by the speed changer, the stepless speed change of a high-delivery-volume automobile, a truck and even a heavy-duty automobile can be realized.