Abstract：Concentration process of ionic sample in capliary electrochromatography (CEC) could be carried out through association of separation mechanism of HPLC and capillary electrophoresis. A model was developed to study the concentration process in CEC. The results show that high resistivity sample, with high organic modifier concentration, could result in excelent concentration performance. A basic drug propatene was chosen at testing sample, which provide over 17, 000 times of concentration. This proves the feasibility of the association mechanism of HPLC and capillary electrophoresis. Effects of operation conditions on concentration performance were also studied.