This paper argues for the property of reversibility toward the interpretation of the aspectual guo in Mandarin Chinese. After thorough examination of studies on its meaning in the literature， I point out that traditional analyses stress too heavily on the experientiality， while recent studies- such as Hsiao (2003)， Pan and Lee (2004)， Lin (2007)， and Wu (2008)- focus too much on the resultant state entailed by guo to derive its meaning of discontinuity. I propose that experientiality or discontinuity still serves as the inherent meaning of guo， yet the resultant state in many events further encodes an extended meaning of reversibility which relates the temporal/physical properties of a discontinued event back to its pre-existing state. The semantics of guo based on this hypothesis is arguably a temporal as well as an atemporal notion. This account of guo is possible provided that the theory of time based on the cognitive grammar as proposed in Ahrens and Huang (2002) is adopted as the framework: in their theory the concept of time is conceived as a moving point over a landscape， and the ego facing the past is attached to this point in relation to the event. Under this assumption， the meaning of guo functions to discontinue the time and provides the ego a viewpoint to conceptualize the reversibility property.