The invention provides an electric actuating mechanism and its adjusting clamp. The adjusting clamp includes a fixing part located at the upper part for fixing and connecting a vertical operation rod and a connection part located at the lower part for connecting the output shaft of the mechanism in a rotation manner. The bottom end of the connection part is provided with an assembly groove which is applied to an assembly rotation pin nail to enable the connection part to swing along the axial line of the rotation pin nail in relative to the output shaft of the mechanism. According to the invention, the connection part is capable of swinging along the axial line of the rotation pin nail in relative to the output shaft of the mechanism. When in connection, if the vertical operation rod does not share the same shaft with the output shaft of the mechanism, the rotation adjusting clamp automatically adjusts the connection position between itself and the vertical operation rod so as to prevent the vertical operation rod from forcible fixing with the adjusting clamp. Convenient to achieve the fixing operation, the problem can be resolved that during the repeated adjustments and fixation of the vertical operation rod, the vertical operation rod is likely to be deformed due to the violent force, therefore, ensuring the torque transmission performance and the turn-off and turn-on performance of an isolation switch.