The influencing factors of rainfall area reduction factor(ARF)are summarized, including watershed area, rainfall duration, return period, terrain, weather type and season. This paper summarizes the algorithm process, basic data types and application scope of “fixed-point fixed-surface” method and “moving-point moving-surface” method for estimating ARF, and analyzes the characteristics and applicability of various methods. It is pointed out that the selection of methods has a significant impact on the calculation of ARF. Although the empirical method of ARF is cumbersome and requires high data, it still has advantages because of its strong applicability in time and space. Analytical method and “moving-point moving-surface” method often rely on simplified assumptions, and their application range is limited. In the future, systematic research should be carried out on the differences of various calculation methods, and spatial analysis of ARF should be developed with the help of high-resolution rainfall data such as satellite and radar, so as to provide more reliable information for engineering design and hydrological simulation.