Abstract: In power dispatching process, the adequacy judgment mainly depends on dispatcher’s experience, which lacks tools to evaluate and early-warn the power system adequacy. on-line adequacy assessment method is proposed for the provincial power grid in this paper. The power system adequacy and area adequacy are analyzed, and decision-making is provided when the adequacy is insufficient. It can enhance dispatcher's abilities to aware, response and active control the power system adequacy, and improve the adequacy level to ensure safe and stable operation of the provincial power grid. The application on dispatching and control cloud shows that the proposed method is feasible, and it achieves on-line monitoring, early warning, and auxiliary decision-making for the adequacy of provincial power grid.