We introduce an alternative separation method, i.e., capillary electrophoresis to examine the polymer/surfactant interaction. The migration behavior of the poly-(vinylpyrrolidone)-sodium dodecyl sulfate (PVP-SDS) model system was screened under a high electrical field for seven different PVP initial concentrations. From the electrophoretic mobilities of formed polymer-surfactant species, the critical aggregation concentration (CAC) of SDS for PVP was determined. The CAC value in the present study was very well matched with the CAC values of this system reported by alternative methods. A strong interaction between polymer and SDS under CAC concentration was observed and the independence of CAC on polymer concentration was experimentally demonstrated.