A sliding plate mechanism of a water replenishment apparatus, comprising the water replenishment apparatus (1), wherein the water replenishment apparatus (1) is provided with two sliding grooves (5) and a cover plate (6) thereon, the cover plate (6) is slidably disposed on the two sliding grooves (5) through two sliding blocks (7), the water replenishment apparatus (1) is provided with a movable slot (4), the movable slot (4) is provided with two upper limit notches (11) and two lower limit notches (12) therein and also comprises a locking device (3) disposed therein, the locking device (3) comprises two pins (31) extending towards the limit notches, each of the two pins (31) is provided with a limit block (32) matching the upper limit notches (11), and the cover plate (6) is fixedly connected to the locking device (3). The cover plate (6) is slidable on an outer casing, and therefore the cover plate (6) can cover a spray output port (10) when the water replenishment apparatus (1) is not in use to maintain the sanitation of the spray output port (10) and can be slid open to expose the spray output port (10) when the water replenishment apparatus (1) is in use, enabling a convenient operation.
