[Objective] In view of the controversies in baseflow separation theory and methods, the research progresse in baseflow separation was summarized in order to provide references for baseflow research.[Methods] We systematically reviewed the definitions of baseflow components, and the development of different baseflow separation methods, which include graphic analysis method, numerical simulation method, water balance method, isotope and chemistry method.[Results] We analyzed and evaluated the theoretical basis, advantages and disadvantages and conditions of application of above methods, and pointed out existing problems and future research trends.[Conclusion] So far, no method for baseflow separation is wide recognition. We still need to further strengthen the baseflow separation theory and method research, to form a unified and perfect theory system, and to determine the baseflow scientifically and reasonably. In addition, the change features and driving factors of baseflow will be an important part of the study of baseflow in the future.