A new continuous baseflow hydrograph separation method based on the Horton infiltration capacity curve and antecedent precipitation index was proposed and developed. Rainfall-runoff data from three watersheds located in different climatic regions of China were selected and used as case studies. Three recent baseflow separation methods, digital filter, nonlinear reservoir and Boussinesq equation, were chosen as parallel schemes to compare with the proposed method. Test and application results indicate that the proposed baseflow hydrograph separation method is in accordance with the hydrological physical process. The proposed method can reduce some of the subjective aspects for the rising limb of the baseflow hydrograph, and is useful for unit hydrograph analysis and for the study of the rainfall runoff relationship.