Abstract: The unit of translation is an essential object in translation studies.The paper holds the view that how to define the unit of translation should not simply start from the syntactic features of source text.The research of the unit of translation may take cognition into consideration,so we might regard the unit of sense in the interpretive theory of translation as the unit of translation.This paper first overviews the domestic and foreign study of the definition of translation units,and points out the limitations of the traditional studies.Then the paper introduces the unit of sense in the interpretive theory which is the combination of syntax and cognition.And in the last part,the paper discusses the rationality and feasibility of viewing unit of sense as unit of translation from three aspects