Abstract: To determine the Cu,Fe,Zn,K,and Na contents in Yin Zhi Huang injection and its four ingredients by FAAS,the samples were digested with concentrated nitric acid and hydrogen peroxide,and the experimental conditions such as wavelength,slit-width,lamp-current,air-acetylene discharge ratio,the height of burner and interference elimination reagent were optimized.2% HNO₃,2% HCl and 6% CH₃(CH₂)₃OH were respectively used as interference elimination reagents for Cu,K,Na,Fe and Zn.Thus,the interference was eliminated and the sensitivity was increased.The linear regression equations and the correlation coefficients were:A_Cu=0.087 4c+0.007 8,r_Cu=0.999 5;A_Zn=0.244 6c+0.072 4,r_Zn=0.999 6;A_Fe=0.065 9c+0.022 1,r_Fe=0.999 9;A_K=0.224 2c+0.008 3,r_K=0.999 5;A_Na=0.613 0c+0.038 0,r_Na=0.999 3.The recoveries of this method were in the range of 95.6%~111%,with a RSD' value of less than 4.0%.This method proved to be simple,rapid with high accuracy and satisfactory results,and it could provide basic data for the quality standard of Yin zhi huang injection.