A　method　for　the　separation　and　determination　of　five　major　opium　alkaloids　(narcotine,　papaverine,　thebaine,　codeine,　and　morphine)　in　pericarpium　papaveris　by　pressurized　CEC　(pCEC)　with　monolithic　column　has　been　developed.　Under　the　optimum　condition,　linear　calibration　ranges　of　narcotine,　papaverine,　thebaine,　codeine,　and　morphine　were　obtained　as　2-85,　2-85,　5-75,　10-65,　and　1065　mu　g/mL,　respectively.　LODs　of　these　analytes　were　1.5-6.0　mu　g/mL.　The　RSD　(n　=　7)　of　the　migration　time　and　peak　area　were　1.94-5.24　and　4.05-8.21%,　respectively.　The　proposed　method　was　successfully　applied　to　the　analysis　of　pericarpium　papaveris　samples.　Average　recoveries　of　79.0-95.9%　at　different　fortified　levels　of　alkaloids　were　achieved　with　RSD　less　than　4.6%.　Meanwhile,　the　mechanism　of　the　separation　of　the　alkaloids　on　the　monolithic　column　was　also　discussed.　The　result　showed　that　the　separation　of　alkaloids　was　mainly　based　on　the　mixed　mode　of　hydrophilic　interaction　(HI)　and　cation　exchange.