Based on the concept of operation flexibility, we study the relationship amongmultiple operation sequences and provide a flexibility measure for operation sequences. Acriterion is proposed to prioritize each operation (rather than sequence). Under the multi-agentarchitecture the criterion can be used to guide the decision-making procedure during production scheduling so that there is an adequate flexibility at each decision point. Experimentalresults demonstrate the efficiency of the criterion when it is used as a scheduling heuristic.It can increase flexibility of manufacturing systems, and consequently improve the performance of the systems.