An analysis method was developed to determine the chemical speciation of Cu, Zn, Fe and Mn in radix scutellariae decoction using atomic absorption spectroscopy(AAS). The decoction can be divided into suspension and soluble species by 0.45 μm filter membrane and the soluble species can be separated into organism and inorganic species by LSA-10 macroporous resin. These elements in water-soluble test samples can be divided into alcohol-soluble and water-soluble by adopting n-octyl alcohol-water allocation system in man-made gastric acidity. Then, the concentration of these elements was determined by AAS, which provided more chemical speciation information about these elements instead of the total amount of them only in radix scutellariae. Detection limit of Cu, Zn and Mn by using the method was all 0.01 μg·mL-1 and was 0.02 μg·mL-1 for Fe. The RSD was in the range of 1.5％-3.6％(n=11) and the recovery rate of soluble species and inorganic species were in range of 96.7％-105.0％. The method has been successfully applied to determine the chemical speciation of Cu, Zn, Fe and Mn in radix scutellariae, which was very important for overall study of radix scutellariae.