Abstract: Failure diagnosability and correctability of discrete-event systems are widely studied.In this paper,we mainly focus on how to correct failure events of discrete-event systems (DESs) under the condition that the controller takes control,for making the system run within accepted states.With the formalization of correctable states and events,we propose a correct method based on cycles of system’s states.Meanwhile,a controller-construct algorithm is proposed.After discussing the rule of failure event’s occurrence while system’s states change substantially,we present respectively a method to calculate the minimal set of states such that the system can be corrected and a feasible solution for the corrected system based on the minimal set of states.