Vertical mill spindle's bracket safety device

The utility model relates to a vertical mill spindle's bracket safety device which comprises bracket bases, brackets and hydraulic cylinders. After rollers are replaced in stop, positioning fixture blocks are additionally mounted on the brackets and can jack the brackets, so that the brackets cannot be closed. Baffle plates are welded on the bracket bases, rib plates and reinforcing baffle plates are welded on the baffle plates, the baffle plates are positioned at the rear ends of the fixture blocks and can function in supporting the fixture blocks, two clamp plates are additionally mounted on each bracket and clamp the bracket to stop the bracket from opening, and welding clamp plate hooks facilitating mounting of the clamp plates are arranged on two sides of the brackets. The two brackets are fixed and cannot be opened by the clamp plates, and equipment and personal safety accidents caused by falling of a coupler in the opening direction of the brackets are eliminated.