Open-tubular　capillary　electrochromatography　(OT-CEC)　with　a　new　stationary　phase,　O-cynaoethyl　chitosan,　has　been　applied　to　the　separation　of　four　cephalosporins.　Several　experimental　parameters　such　as　the　buffer　type,　pH　and　buffer　concentration,　mobile　phase　composition,　and　applied　voltage　were　evaluated.　Baseline　resolution　of　the　studied　cephalosporins　could　be　achieved　within　14　min.　The　calibration　curves　of　cefixime,　cephalothin,　cefuroxime,　and　cefoperazone　were　linear　over　the　concentration　range　of　0.6-50,　0.8-50,　0.8-50,　and　1.0-50　mu　g/mL,　respectively.　The　detection　limits　(S/N　=　3)　of　four　cephalosporins　ranged　from　0.2　to　0.4　mu　g/mL　and　the　recoveries　of　the　milk　samples　were　about　82.0-96.7%　(RSD　＜=　3.8%).