Abstract: A clamping device includes a base, a driver coupled to the base, a movable clamping jaw coupled to the driver and the sliding rail. The base includes a sliding rail, and a fixed clamping jaw coupled to the sliding rail. The movable clamping jaw is coupled to the driver and the sliding rail. The driver is configured to move the movable clamping jaw along the sliding rail towards the fixed clamping jaw. The movable clamping jaw includes a movable member having a main body. The main body defines two avoidance grooves at opposite side thereof. A side surface is formed at a side of each avoidance groove and spaced from the sliding rail.