A method and apparatus for mold protection of motor-driven clamping unit is provided. The method and apparatus is based on high response characteristics of the motor and a new control method. A continuously variable restrictive motor output scheme is used in conjunction with the mechanics characteristics of the toggle mechanism to maintain a substantially constant mold protective force at all positions. Further, the mold protective force can be adaptively adjusted with respect to different types of molds and motional conditions so that the mold can be adequately protected whenever abnormal condition occurs during mold closing action. The motor output will thus not unduly increased to a great level that would damage the mold, the machine, or even the operators. The drawbacks of the prior art are thus eliminated.