<p>A method for treating a stainless steel refining slag which comprises treating a slag generated in a refining process for stainless steel so as for the slag to have a basicity of 1.3 to 4.0 and then mixing the slag in molten state with a substance containing a sulfur having a valency of zero or a negative value in an amount such that the slag has a sulfur content of 0.2 wt % or more. The method can be used for modifying the above slag so that Cr<6+> does not elute from the plug substantially perfectly, which results in the effective use of the slag as a material of a pavement base which is free from the danger of environmental pollution. It is preferred for efficient modification that the cooling of the slag mixed with the sulfur-containing substance from 1200 DEG C to 400 DEG C is carried out rapidly, i.e, within a time of 48 hrs.</p>
