A computerized base-flow separation method with BFI program was used to determine the base-flow index from daily discharges based on the measurements of the 1994-2003 water years at the Hecha Hydrolometric Station on the Fenhe River. By Comparing with the traditional separation methods, the estimates with BFI program were closely related to that with the beeline separation method. The analysis shows that the computerized separation technique is viable and objective to indicate the changing trends of base-flow in this area. Additionally, it can overcome the lack of artificiality and randomicity of manual methods and automatically process large quantity of data.