It was found that as a result of reviewing the availability of melted slag(granulated slag) as an aggregate material for sub-base, the slag itself couldn't be used owing to the material characteristics. However, it was also revealed that the physical characteristics(No.200 penetration rate, specific gravity, absorption ratio, moisture content, sand equivalent, particle size distribution) of melted slag mixed 1:1 with mineral filler met KS Quality Requirements, and the modified C.B.R value was 68, which is superior to the specification, 30. Considering also the max dry density and modified C.B.R value according to the replacement rate of mineral filler, it deems that the melted slag mixed 1:1 with mineral filler could be used for sub-based.