The invention discloses a full-automatic intelligent water-controlled farmland irrigation water gate control system. The system is divided into a switch control device, an anti-backflow device and a floating ball device; a water gate is placed on the field ridge, the switch control device and a floating ball are placed in the field, and the anti-backflow device is placed in the water channel; whenthe field is in water shortage, the switch control device is automatically started, the floating ball descends, the gate is opened, and water enters the field; when the water in the field reaches a set value, the switch control device is automatically started, the floating ball rises, and the gate is closed; when no water exists in the water channel, the anti-backflow device controls the switch control device, when the field is in water shortage internally, the switch control device cannot be automatically started, the floating ball cannot descend, the gate cannot be opened, so that the waterin the field is prevented from flowing backwards into the water channel, and full-automatic intelligent water control is realized.