The spatio-temporal metaphorical expressions of Qian “front” and hou “back” in Chinese can indicate either the past or the future, the interpretation of which could not be resolved by resorting to the traditional “Moving Ego” and “Moving Time” models. Building on related cross-linguistic research findings regarding frame of reference, this study proposes that Moore's (2006) and Nú1 ez & Sweetser's (2006) Ego-RP and Time-RP models can resolve the opposing interpretation of qian and hou temporal expressions. Qian referring to the past and hou to the future adopt Time-RP model while qian referring to the future and hou to the past employ Moving Ego which is a subtype of Ego-RP model. Our analysis gives a unified account to the interpretation issue of qian and hou spatio-temporal metaphorical expressions by revealing their predominant employment of Time-RP model with Moving Ego of Ego-RP only as a supplementary.