Abstract: As the unit of human knowledge, event is used to describe all kinds of knowledge in the world. Action which is one of the main factors in event describes the changing processes of world states in a specific period of time. As we know, there are different states in different time and the main reason of states changes is caused by action. Therefore, it is necessary to embrace temporal information into the representation about action to describe these changes. In this study, we first proposed a temporal description logic T-ALC, in which the temporal information as a constraint of instances was added to ABox. It provided a kind of decidable approach to deal with the states changes of objects in action. Then, we defined the syntax and semantics of action based on T-ALC. Especially, the semantics of action can be transformed into the changing processes of interpretations and the calculation of new interpretations and ABox were also given. Finally, several inference services of action in different time were studied.