Abstract: A water stopper for sink that is used in a water stopper base includes a water stopper body, a fixed rod, a plug and a pulling head. The plug is a rubber block having a through opening in the central portion thereof, and a trough is upwardly formed from the bottom surface of the plug. With the trough, the plug is able to sustain pressure from every side due to its resilient reformation. A circular protrusion is formed at an enlarged periphery of the plug, so that the lower portion of circular protrusion forms a guiding section, the rear end of which is tapered toward the trough to form a curved bottom edge.