The utility model relates to a full-automatic grinder. The full-automatic grinder comprises upper and lower grinding discs arranged at an upper side and a lower side and suitable for grinding each other, and a main body, wherein the lower grinding disc is fixed on the upper end of the main body, and the main body is internally provided with a low-speed motor used for driving the upper grinding disc to rotate. The full-automatic grinder is characterized in that a separable water tank is arranged at an upper side of the main body, the water tank is internally provided with a storage vat which can isolate from water, the movement trajectories of a discharge port of the storage vat and a blanking hole on the upper grinding disc or inner side parts of the movement trajectories are oppositely arranged at upper and lower sides; and a central through hole of the slow-speed motor extends out of the upper grinding disc, and is in screw-thread fit with a nut. A grinding extruding technology is applied to the full-automatic grinder, disadvantages caused by conventional high-speed cutting of foodstuffs are prevented, the motor speed only reaches 40-80r/min, and with the cooperation of the upper and the lower grinding discs, the foodstuffs are fully ground; and the full-automatic grinder is low in vibration and noise.