White ginseng was recently reported to be illegally sulfur-fumigated by some herbal farmers or wholesalers during post-harvest handling and storage.In present study, an UPLC-QTOF-MS/MS method was developed to reveal transformation of ginsenosides in white ginseng induced by sulfur-fumigation.Chromatographic conditions were optimized to separate newly-generated more polar ginsenoside derivatives.And some parameters of MS, i.e.the temperature and flow rate of nebulization gas for ion source, and the capillary and cone voltages were optimized to balance the ionization of original ginsenoside and its newly-generated derivatives.