Abstract: Leafy vegetablesare the daily consumption food, a quick and accurate way in the determination of heavy metalsinplant samples is very important for the supervision and management of food safety. Inductively coupled plasma (ICP) is auniversal analysis technique for inorganic elements, especially for heavy metals,ICPis widely used in the analysis for biological and environmentalsamples. However, differentdigestion methodscould cause large differencesto the determined results. The authorsgained the proper acid digestion system,which wasHNO3:H2SO4:HClO4=3:1:1, based on the comparison of the effects of several ordinary digestion methods including the volumes of the acid used and their ratio on the concentration of Cu, Zn, Cr and Pb in pakchoi samples. The results showed that the relative standard deviations (RSD ) were in the range of 3.50%-6.33%, and the recoveryrates were above 92%for Cu, Zn and Cr, while 78% for Pb. The proposed method could be used for the examination of these heavy metals.The experiment provideduseful technical guidance for the determination of heavy metals in leafy vegetables by ICP-OES.