An automatic water regulator includes a water tank component and a base component disposed thereunder. The water tank component includes a box body, a water inlet arranged in a middle portion of the box body, a spring, a sealing ring, an ejector rod sleeved by the spring and inserted into an intermediate position of the water inlet, an ejector shaft, a tray disposed on a side of the ejector rod, a floating bucket disposed at a bottom portion of the box body and away from the side of the ejector rod, and a floating bucket shaft disposed on a middle portion of the floating bucket. The base component includes a main base body and a supporting rib therein and below the tray. The sealing ring is disposed on top of the ejector rod. A bottom end of the ejector rod is connected to the floating bucket.