The ambiguity of the term"knowledge"has hindered the development of the sociology of knowledge.An appropriate typology of knowledge can help us to systematize the sociology of knowledge from the per-spective of the object of study.This article first discusses the multiple established knowledge classifications in sociology,noting that the everyday ideas/specialized knowledge satisfies the four criteria of a systematic sociology of knowledge.It then examines the different forms of everyday ideas/specialized knowledge,analy-zes the understanding of the classification in schools such as pragmatism,and summarizes the connotation of the classification.On this basis,it refines the distinction between everyday ideas/specialized knowledge and briefly describes eight areas of the sociology of knowledge by summarizing research topics.Systematizing the sociology of knowledge with the help of knowledge classification is both a manifestation of the discipline re-flexivity and an important step for the future of the sociology of knowledge.