Workpiece locking device and method for machining equipment

The invention discloses a workpiece locking device for machining equipment and a method of the workpiece locking device, and belongs to the technical field of machining, a sliding plate drives a clamping plate to position a workpiece main body, the purpose of locking the workpiece main body from the outside is achieved, after machining operation on the inner wall of the workpiece main body is completed, a rotating disc is rotated in the same way and in the reverse direction, and the workpiece main body is locked. The material blocking plate drives the four clamping plates to be far away from each other through the four sliding plates, the outer wall of the workpiece body is completely exposed outside, the supporting rods drive the supporting plates to make contact with the inner wall of the workpiece body through the sliding blocks, the purpose of locking the workpiece body from the inside is achieved, and therefore the outer portion and the inner portion of the workpiece body can be alternately locked; the w