Abstract: Ideology, normally a concept in political studies, is also a key concern in sociolinguistics, pragmatics and critical discourse analysis in the last thirty years.Reviewing relevant studies of ideology in these linguistic fields, this article identifies four features of the concept of ideology in linguistic studies, namely, ideology being characteristic in terms of consciousness, social position, power relation, and discourse realization.The article continues its investigation by highlighting three roles ideology plays in linguistic studies, namely, ideology being the content linguistic study is to reveal, the issues linguistic study investigates, and the tool by which linguistic research is to be done.Finally, the article relates what is discussed here with relevant issues at home, proposing that further concern of ideology in linguistic studies is needed for a better understanding of speaker's agency in the process of decoding the social meaning of language use as well as for theoretical innovations.