Scholars have different views on how to use the early Buddhist literature to study the early Buddhist teaching. Therefore, this paper summarizes three typical methods: single document method, common document method and hierarchical document method, and analyzes their advantages and disadvantages. This paper puts forward four elements related to literature methods for the purpose of exploring early Buddhist teaching: research purpose, understanding of early Buddhism and literature, and research process. It defines the six principles of objectivity, comprehensiveness, commonality, effectiveness level, practice and doubt in the use of early Buddhist literature. According to the similarities and differences of early Buddhist documents, the types of documents are divided and their functions are explained. Centered on the research purpose and based on the principles, this paper demonstrates the methods of various literature in different research stages. This paper holds that the common classics of the northern and southern literature constitute the core of the early Buddhist literature and the basis for understanding the early Buddhist teaching. The common content of different classics provides supplementary evidence for understanding the early Buddhist teachings; Screening and judging the different contents in the literature is the way to deeply understand the teachings. To explore the early Buddhist teachings, we should start from the common classics and establish its basic theory and practice system. Through the analysis of different classics and different contents, we can understand the unclear teachings in the common classics. We should leave a question open about what cannot be solved by the extant literature, and we should not use the literature one sided.
