An automatic water changing system includes an aquarium, a filter tank, a controller and a human machine interface (HMI). An inlet valve of the aquarium is disposed corresponding to an inlet pipeline. A drain valve is disposed corresponding to a drain pipeline. A pump of the filter tank is connected with a first connecting pipeline and pumped the water contained in a cabinet to a tank body by the first connecting pipeline. The water in the tank body overflowed to the cabinet by a second connecting pipeline. The controller controls the inlet valve, a drain valve and the pump ON/OFF, so as to control the water level of the tank body. A user can input setting parameters of the controller by the HMI, and automatic control the water changing time and the water changing volume of the aquarium by the control through the HMI.一種自動換水系統包括一魚缸、一過濾槽、一控制器及一人機介面。魚缸之一進水閥對應設置於一進水管路,一排水閥對應設置於一排水管路。過濾槽之一泵浦連接一第一連接管路並將一箱體內的水透過第一連接管路輸送至一缸體,缸體內的水透過一第二連接管路溢流至濾槽箱體。控制器控制進水閥、排水閥及泵浦的開啟/關閉,以控制缸體的水位。使用者可透過人機介面輸入控制器的設定參數,且藉由人機介面透過控制器自動調控魚缸的換水時間及換水量。1‧‧‧自動換水系統11‧‧‧魚缸111‧‧‧缸體112‧‧‧進水管路113‧‧‧進水閥114‧‧‧排水管路115‧‧‧排水閥12‧‧‧過濾槽121‧‧‧過濾槽箱體122‧‧‧泵浦123‧‧‧第一連接管路124‧‧‧第二連接管路127‧‧‧第一液位開關127a‧‧‧第二液位開關14‧‧‧感測器17‧‧‧水質過濾材料18‧‧‧水流開關
