The high penetration of renewable energy introduces strong uncertainty into power system operating conditions, making it difficult for conventional planning methods to effectively satisfy N-1 security verification requirements. To address this issue, this paper proposes an N-1 security-constrained 8760-hour power flow generation method (N-1-SC-8760-PFGM), formulated as a mixed-integer nonlinear programming (MINLP) problem. To overcome the computational intractability of direct solution, an energy-power-reactive power co-optimization method is developed based on objective consistency and solution path coordination. By employing a consistency-oriented objective function, a pre-embedded N-1 constraint mechanism, and a “verification–augmentation–re-optimization” solution strategy, the proposed method overcomes the limitations of traditional sequential optimization approaches, such as stage-wise independent objectives, insufficient coordination of N-1 constraints, and the lack of iterative re-optimization mechanisms during operating state adjustments. Case studies on modified IEEE 39-bus and IEEE 300-bus systems demonstrate that the proposed method achieves superior convergence and computational efficiency compared with conventional decomposition-based methods, and can efficiently generate full-year power flow profiles that satisfy N-1 security constraints.