Abstract: There are many kinds of spare parts and optional suppliers in metallurgical enterprises, so it is more complicated to select suppliers of spare parts than to select those of raw materials. The multi-attribute decision method was used for selecting the suppliers on the basis of the rough set theory. First, when a decision attribution system was selected, the rough set theory was used to analyze the relationship between historical attribute data and historical suppliers selecting results in order to find out objective weights for each attribute. Both objective and subjective weights were considered in synthetical weights. Then, with the synthetical weights and normalized results of attribute data of candidates, all the suppliers were evaluated. Finally, a case was used to prove the feasibility and validity of this method.