A method for manufacturing a reconstituted stone raw material by using a molten slag includes: controlling a temperature of the molten slag at 1400° C.-1500° C., and performing a cast-molding process on the molten slag; and maintaining the cast-molded slag at a temperature of 800° C.-1000° C. for 1-5 hours in a non-reducing atmosphere, and then gradually cooling the cast-molded slag to a room temperature within 2-5 hours to obtain the reconstituted stone raw material. An energy-saving and efficient method for comprehensively utilizing the blast furnace slag is provided. The produced reconstituted stone raw material has such characteristics as stable color quality, abrasion resistance, pressure resistance, strong adhesiveness, low coefficient of expansion and low shrinkage ratio.