Abstract: The solving of the day-ahead generation schedule is generally to obtain an initial solution without consideration of the security constraints, and then the security-violated constraints are included in the generation scheduling model for iterative calculation. If only the security-violated constraints are considered in the solution, the new security-violated constraints will be generated with the increase of iterative calculation numbers. To improve the security constraint feedback mechanism, an identification method of the constraint coupling relation is proposed and applied the background of spot market schedule solving.Firstly, the closed-loop solving procedure of day-ahead generation schedules in the background of spot market is analyzed based on the security region. Secondly, the concept of coupling distance of security constraints is proposed, quantitatively depicting the coupling relations between the security-violated constraints and non-security-violated constraints. Besides, the adaptive solving method for coupling distance is designed. Finally, the identification of security constraint coupling relationship is included in the closed-loop solving framework of day-ahead generation schedules, and then the iterative process information is used to find the potential security-violated constraints, assisting the analysis of the coupling degree of different constraints in power system operation. Case studies of the IEEE 118-bus and IEEE 300-bus systems verify the effectiveness and applicability of the proposed method.