Abstract: The effect of Fe₂O₃ on retained aluminum in deposited metal, mechanical properties and fracture analysis has been elucidated in this study. The results show that with the increasing amount of Fe₂O₃, in the flux core, the melting point of the pretreated compounds, the content of retained aluminum in deposited metal, the size and the number of inclusion, yield strength and tensile strength decrease, while the toughness of the deposited metal and the dimple proportion of the fractue increase obviously. The inclustios in the weld are Ba,Ca,Al,Mg in round and rectangular form predominantly. However, electrode with the Fe₂O₃ content exceeding 4.5% is extremely sensitive to voltage and macro-porosity can be found in the weld metal. So, in the view of the processing properties and the mechanical properties, the range of 2.5~3.5 percent by weight of core to electrode is preferred.