This paper reports on the application of "Out-of-Kilter Algorithm" (OKA) to the real power economic dispatch with security constraints. The network flow programming is characterized by simple manipulation, fast and reliable convergence, while the OKA can treat nonzero lower bounds and may initiate with any set of flows (including infeasible flow) which satisfies Conservation of flow. The major procedure and numerical example of OKA are given in this paper. The calculating results for economic dispatch on test systems have shown that the method is feasible and effective.