Problem statement: So far, various approaches have been raised regarding the design of infill buildings that usually, categorization of these approaches has been focused on physical topics. Therefore, it can be said that the issue of physical criteria is very important in the design of infill buildings. In this regard, according to the lack of a unified discourse about effective physical criteria to select approaches from theorists point of view, as well as the existence of obvious differences in the introduced criteria and the lack of some criteria in these definitions, it seems necessary to consider all the effective physical criteria and achieve a coherent set from them.
Research objective: Therefore, this study’s primary goal is to analyze and investigate various theories to scrutinize and achieve a comprehensive complex of effective physical criteria in selecting and defining the approaches and the other purpose of the research is to classify those criteria in the form of main criteria and sub-criteria to use them in designing and evaluating infill buildings.
Research method: Regarding the methodology, it can be said that this descriptive-analytical research has used the logical reasoning strategy and the content analysis technique using library recourses to organize the indicated criteria by theorists and related organizations in a more comprehensive system.
Conclusion: Therefore, all those criteria are classified as the main criteria in four general areas: 1. Position 2. Form & shape 3. Scale and proportions 4.Material appearance characteristics, due to having the highest frequency and importance in the studied literature of research. Then, their sub-criteria are presented in the form of a diagram  to help determine different approaches to the design &evaluation of infill buildings.