Abstract: HPLC-ICP-MS hyphenated technique was used for the Se speciation analysis. Se-methylselenoL-cysteine (C₄H₉NO₂Se) and DL-selenomethionine, (CH₃Se(CH₂)₂CH(NH₂)COOH) were successfully separated by both Ion-Pair HPLC and size exclusion chromatography-HPLC, then on-line measured by hyphenating with ICP-MS. The linier dynamic range better than 3 orders (from 5 μg/L to 500 μg/L for both Se species) were obtained for IP-HPLC-ICP-MS. The detection limits and the compound independent calibration (CIC) phenomenon for HPLC-ICP-MS were discussed. The good potential of HPLC-ICP-MS method were shown by the experiments for the se-speciation analysis.