Abstract: Through the method which was used for a kind of special specimen preparation for coating artificial fracture, the fracture specimens of hot-dip 55%Al-Zn alloy steel coating which were produced in industrial condition were obtained successfully. To observe these specimens by SEM and analyze by energy spectrum, the fracture characteristics of coating microstructure and micro-components were indentified. The results showed that the coating was consisted of two layers, one was Al-Zn alloyed layer of the outside surface, and the other was Fe-Al-Zn-Si alloyed transition layer between sheet and Al-Zn alloyed layer. The growth process of transition layer and the nucleation and growth process of zinc enrichment phase were also found.