The invention discloses a gear clamp for an efficient gear machining machine tool. The gear clamp comprises a body, a rotating disc and a driving gear, wherein a rotary shaft is rotatably mounted on the body; a one-way clutch which enables the rotary shaft to only rotate clockwise relative to the rotating disc is arranged between the upper end of the rotary shaft and the rotating disc; a pluralityof gear supporting round discs are rotatably mounted on the rotating disc; the distances from the gear supporting round discs to the rotating center of the rotating disc are equal; a gear shaper located on the periphery of the rotating disc is also arranged on the body; a gear clamping device is mounted on each gear supporting round disc; a clamping seat rotation driving hollow shaft is mounted on each gear supporting round disc; a driven gear is mounted on the clamping seat rotation driving hollow shaft; an overrun clutch is arranged between the rotary shaft and the driving gear; a rotatingpressure head is rotatably mounted at the lower end of the rack; and the rotating pressure head will rotate along with rotation of a reversed cone-shaped head rather than block rotation of the reversed cone-shaped head along with the supporting disc.