This paper aims to discuss John Sinclair's phrase theory and its key concepts, his major contributions to the study of meaning, and the inadequacies as well. It is argued that Sinclair's major achievements in the study of meaning can be attributed to his phrase theory, that its core components are phraseological items and lexical items, that his model of extended unit of meaning, consisting of core, collocation, colligation, semantic preference and semantic prosody, can be applied to the description of both lexical items and phraseological items. Sinclair's major contributions to the study of meaning include that to a great extent he turned the linguists' attention from context to cotext, that he developed and improved the KWIC analysis, upon which the model of extended unit of meaning was formulated, that he put forward the theoretical framework of his phrase theory, getting theoretically ready for the study of meaning. The inadequacies are that the notion of semantic prosody is still vague, preventing the model of extended unit of meaning from being fully exploited, and that paraphrase has not been theoretically evaluated, resulting in language users' meaning not being reflected in his study of meaning.
