The invention discloses an alkaline button battery. The alkaline button battery comprises an anode cup, a cathode top, a sealing ring, zinc gel, an anode cake, a diaphragm and electrolyte, wherein theanode cake is separated from the zinc gel through the diaphragm; the anode cup and the cathode top are insulated from each other through the sealing ring; the sealing ring comprises an annular body made from plastic; the annular body comprises a vertical annular part and a lateral annular part; the lateral annular part is positioned at the bottom of the inner side of the vertical annular part; aflexible annular protection part with the thickness gradually reduced is integrally formed at the inner side end of the lateral annular part; the lower surface of the lateral annular part and the lower surface of the flexible annular protection part form smooth transition; when the positive expansion of the anode cup drives the diaphragm to move upward, as the flexible annular protection part is increased, the flexible annular protection part is extruded by the diaphragm and is tilted upward, the diaphragm cannot be punctured, and the occurrence of the phenomenon of short circuit of the buttonbattery is avoided.