Abstract: Dynamic events occur in the process of the flexible machining system unexpectedly, which interfere the execution of the existing scheduling plan, and it is difficult to maintain better objects such as energy consumption. In view of this problem, a dynamic optimal scheduling method for energy consumption under the dynamic events with new task insertion and machine failure and repair is established based on the flexible machining system Petri net (FMSPN). At the moment when dynamic event occurs, FMSPN is re-established and the law of energy consumption under each equipment in the system is merged to obtain the total energy consumption model of the system from the moment to the makespan at the same time. Then the energy consumption model is re-optimized based on modified dynamic programming method, and the scheduling plan after the moment with the better energy consumption object is solved. Finally, the reliability of the FMSPN in the optimal scheduling process and the feasibility of the method under dynamic disturbances is verified by simulation.