Abstract: Semantic vagueness has long been a subject of studies in both logicsemantics and cognitive psychology，and the latter has given a fruitful explanation from a new perspective.Based on the look at and the comparison between these two methods，the auther thinks Fillmore′s theory of frame and Lakoff′s idealized cognitive model provide a good access to further studies of vagueness of languages.However，idealized cognitive model is still an abstract and fixed psychological model，and the relations and interactions between models are changeable，which is similar to the distinction between semantics and pragmatics.

Key words: vagueness, category, idealized cognitive model, logic semantics, cognitive psychology