The invention discloses a water production control method, a water production control device and an ultra-pure water preparation system based on electric ball valves adjustment. The method comprises an initialization step, an open/close control step, a pressure difference calibration step, and a linkage adjustment step. In the initialization step, concentrated water side discharge electric ball valve and return electric ball valve unit open and close degrees at full open and full close of the concentrated water side discharge electric ball valve and return electric ball valve are detected. In the open/close control step, the open and close of the concentrated water side discharge electric ball valve and return electric ball valve are controlled according to the unit open and close degrees; real-time open and close degrees are recorded; and the real-time and unit open and close degrees are corrected according to the detection signal feedback. In the pressure difference calibration step, the pressure difference between reverse osmosis membrane water inlet side and concentrated water side when the concentrated water side of the reverse osmosis membrane reaches a target flow rate is obtained through adjusting the concentrated water side discharge electric ball valve and return electric ball valve open and close degrees, and is adopted as a target pressure difference. In the linkage adjustment step, through adjusting a high-pressure pump and the concentrated water side discharge and return electric ball valve open and close degrees, the target pressure difference and the target flow rate are achieved. With the method, the device and the system provided by the invention, cost is reduced, and control precision is improved.