Complex event evaluation systems and methods are disclosed. A mathematics model for complex events and corresponding factors, and calculates a critical level of respective complex events according to weightings of respective factors in the mathematics model are provided. If several complex events occur simultaneously, a priority of respective complex events is calculated according to the historic occurrence of respective complex events. The critical level and priority of respective complex events are provided to users for decision making. Additionally, the mathematics model is established and adjusted according to the feedback scores for complex events.