Copper anode smile is an important by-product of metallurgical industry which contains a variety of precious metals and valuable metals, so that its comprehensive recycling and utilization is increasingly concerned. It is difficult to use conventional method to dissolve the Sb in pretreated residue of copper anode slime (enriched slag). Therefore, it is necessary to develop an accurate and simple method to realize the quantitative analysis of Sb. Here, a comprehensive analysis method was developed for the chemical composition, phase and microstructure of the enriched slag by means of X-ray fluorescence spectroscopy, X-ray diffraction and field emission scanning electron microscopy by using alkali fusion procedure. The analysis results showed that the chemical composition and physical structure of the enriched slag are complex, and its components are chemical stable and intergrowth closely. Sb exists in the form of high state antimony acid salt with a stable structure. The samples were digested by Na2O2 fusion method, and the standard series of synthetic standard samples were synthesized. The content of Sb in the enriched slag by flame AAS was 8.23% with the relative standard deviation of 0.97%, the detection limit of 0.072% and the recoveries of 94.9%～99.2%. Here, the enriched slag can be completely dissolved by this simple method, which does not require the use of special reagents and instruments. Because the synthetic standard sample is similar to the actual sample, the interference of coexisting substances caused by the complicated chemical composition can be eliminated. This method with high sensitivity and good accuracy in comparison experiment, can be used for the quantitative determination of Sb in pretreated copper anode slime.