Metaphors are not only a rhetorical device,but a common way of human thinking,powerful cognitive tools for our conceptualization of abstract categories,the mapping across cognitive domains in conceptual systems,and the interactions between contexts.Under cognitive linguistics,the constraints of cognitive contexts in metaphor construction are analyzed systematically.The finding is that cognitive context,with the cognitive participants' knowledge script and psychological schema as the working units,plays a decisive role in cognitive construction over metaphors,which is in accordance with the three representations of cognitive studies on metaphors,and the cognitive nature and basis of metaphors.Therefore,it is a basic rule that cognitive construction over metaphors is constrained by cognitive context which has therefore to be taken into account in interpreting metaphors.