Abstract: Plant root respiration is the dominant component of total soil respiration, which in turn is closely related to the carbon cycle of terrestrial ecosystems and a significant factor in global climate change. Research focused on plant root respiration is critical for understanding ecosystem carbon budgets and the biosphere’s carbon balance. Root respiration is affected by both environmental and biotic factors. Root respiration rates and their contribution to soil respiration varies greatly in different ecosystems. The main methodologies in research on root respiration include direct measurement (such as isolated methods/in vitro root methods, isotopic methods and cuvette methods) and indirect methods (such as the root exclusion method and calculation method). Plant root respiration is affected by soil temperature and humidity, nutrition condition and root size, root order, root biomass and root mycorrhiza. This paper reviews the various methodologies and factors held to influence plant root respiration in order to provide the basic theory needed for subsequent research. Future research directions are also suggested.