Smart gel water plugging agent is a selective water plugging product based on special polymers, which forms glue in water but it is dispersed in oil. By injecting the fluid system into the plugging section without moving the tubing, the fluid system is controlled to form colloid under the formation temperature and set time. Under the condition of formation temperature, the fluid system will form a colloid with certain strength when it encounters formation water or water channels, but it will not produce colloid when it encounters oil or oil channels. The system can maintain a long-term effective strength under the condition of formation water, so as to achieve the goal of selective water plugging in the formation.