A sandglass fallback jack comprising a base that supports a shore is characterized in that the upper surface of the base is fixedly connected with an external column, the inside diameter of the external column is less than the diameter of the shore, the outer wall of the external column is welded with at least three radial positioning elements, the lower part of each positioning element is vertically welded with the column wall of the external column, the upper part protrudes out of the inner wall of the external column at a radial direction and holds up the outer wall of the shore, the lower edge of the external column is provided with a sand leaking hole, the inside of the external column is filled with sand. The sandglass fallback jack can regulate falling fallback height as required and lead a weighted thing to slowly fall to a required height. Meanwhile, in the process of falling, the falling can be stopped by blocking the opening of the sandglass with sundries, the manufacture is simple and the operation is convenient and fast.