Abstract: High-quality purification of lithium (Li) is crucial in measuring ⁷Li/⁶Li ratios of whole rocks precisely by MC-ICP-MS. Many scholars have proposed traditional manual Li purification methods by cross-combining the types of eluents, types of resin, resin particle size, column tube size, and resin volume. However, the process is still cumbersome. In contrast, high-pressure ion chromatography (HP-IC) provides single-step separation, shorter durations, and online quantification; it is underutilized due to insufficient systematic research on its elution processes. Here, an automatic purification method of Li by HP-IC was established by optimizing IC parameters, laying a foundation for the wide application of IC in the field of isotope purification. The testing results of Li collections for four national geological standard samples indicate that the recovery rate exceeds 99.3%, and the blank measurement is lower than that of the traditional manual column method. The amount of separated Li also meets the demand of MC-ICP-MS for Li isotope analysis. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202407310165.