Abstract: As a relatively stable component of river runoff, baseflow is also the main source of runoff during dry season in arid and semi-arid areas, which is of key significance to the optimal allocation of water resources and the maintenance of ecological environment in the basin.The accuracy of baseflow separation results has a great influence on the prediction of hydrological processes in the basin and the investigation of baseflow change rules. As an important tributary of the middle reaches of the Yellow River, the Fen River is related to the economic development of the whole middle reaches area, and the study of baseflow change of the Fen River can effectively characterise the change mechanism of the baseflow in the middle reaches of the Yellow River, so it is particularly important to select the appropriate separation method.There are many baseflow separation methods, among which numerical simulation method is widely accepted in practical application because of its objectivity, repeatability and ease of operation, as well as efficient and convenient processing of long series of lengthy and complicated data. Based on Jingle hydrologic station daily runoff data from 2006 to 2014, eight commonly used numerical simulation methods are used to separate the base flow, and the intra-annual and inter-annual variation characteristics of the runoff are analyzed. The characteristics are analyzed from three perspectives: the base flow index of instability coefficient, standard deviation and coefficient of variation; we also study the correlation of base flow index in typical years of base flow and runoff process. To test the validity of the base flow separation results, three indexes are selected:Nash-Sutcliffe efficiency coefficient, the average relative error and the correlation coefficient. The results show that: The Chapman filtration method, the Chapman-Maxwell filtration method and the Eckhardt filtration method proved to be the most suitable methods for separating base flow at the Jingle hydrological station. The calculated BFI values are 0.491, 0.495 and 0.496 respectively. The results of the study provide technical support for the study of baseflow separation and change rule of baseflow in the middle reaches of the Yellow River, and provide scientific basis for the rational use of water resources in the middle reaches of the Yellow River and better construction of the local ecological environment.