Evidence synthesis is the use of standardized, clear and rigorous methods to bring together and merge existing research data, knowledge and information, focusing on specific research questions, in order to provide a basis for relevant medical and health decision-making. At present, there are many types of evidence synthesis methods, the number of related applied research has proliferated, however, it is easy to confuse between different methods, which leads to problems such as misuse and abuse. The choice of inappropriate synthesis method will reduce the credibility and applicability of evidence. Clarifying the path and link of the selection of evidence synthesis methods will play a positive role in promoting the standardization of evidence-based evaluation. Thus, this paper briefly describes the development and classification of evidence synthesis methods, and reviews 18 representative evidence synthesis methods and its application examples in the medical field including systematic review. It also introduces the “Right Review”, an evidence synthesis method selection tool that has been developed and put into use in recent years, and clarifies the limitations of the current selection tools and methods. At the same time, referring to existing tools, theories, and models, the selection path for different evidence synthesis methods and the decision process of evidence synthesis are proposed. To provide reference for researchers to choose the evidence synthesis method reasonably.