The purpose of sociology of law is sociological and scientific study of the social being of law. Sociology of knowledge is a field of sociology that studies social determination of knowledge to show which part of human knowledge (shape, content, or both) has been caused by social factors. In this article, sociological concepts and views are used to study and categorize legal knowledge, four types of which have been introduced (legislative, judgmental, intellectual, and instructional). In this study, the necessity of basing legislative legal knowledge on religion, the rapid evolution of legal knowledge and the key role of judgmental legal knowledge have been analyzed in a sociological framework.