OBJECTIVE： To study the difference of the contents of copper， lead， cadmium， mercury and arsenic in the single decoction and combined decoction of Huangqi jianzhong decoction （containing Astragali radix， Cinnamomi ramulus， Paeoniae radix alba， prepared Glycyrrhiza uralensis， Zingiberis rhizoma recens， Jujubae fructus）， and to provide reference for safe use of TCM in clinic. METHODS： Samples of medicinal materials， single decoction and combined decoction were prepared from different medicinal materials； the contents of copper， lead， cadmium， mercury and arsenic in various samples were determined by atomic absorption spectrophotometry， which were compared with the limits of copper （＜20 mg/kg）， lead （＜5 mg/kg）， cadmium （＜0.3 mg/kg）， mercury （＜0.2 mg/kg） and arsenic （＜2 mg/kg） content stated in 2015 edition of Chinese Pharmacopeia and Green Trade Standards of Importing Exporting Medicinal Plants Preparations. The difference of 5 elements contents were compared between single decoction and combined decoction. RESULTS： Among the 6 medicinal materials， the cadmium content of Cinnamomi ramulus and Zingiberis rhizoma recens exceeded the standard， 0.32， 0.74 mg/kg， respectively （copper， lead， mercury and arsenic all met the requirements）， and the 5 elements content of other medicinal materials all met the requirements； the contents of copper， lead， cadmium， mercury and arsenic in the single and combined decoction meet the requirements； compared with the medicinal materials， the contents of copper， lead， cadmium， mercury and arsenic in the single decoction were lower （P＜0.01）； compared with mixture of single decoction， the contents of copper and mercury in combined decoction were lower （P＜0.01）， while the contents of lead， cadmium and arsenic in the decoction were higher （P＜0.01）. CONCLUSIONS： For Huangqi jianzhong decoction， combined decoction can reduce the dissolution of copper and mercury， and increase the dissolution of lead， cadmium and arsenic. The possible reason is that the interaction of various components in the co-decoction process changes the solubility of copper， lead， cadmium， mercury and arsenic.