Abstract: Preparing high added-value materials from molten slag directly by modifying molten slag has drawn a great interest in the utilization of molten slag because of its high efficiency during the integrated utilization of the heat and slag. In this paper,molten steel slag and sands were selected as typical molten slag and modifiers,respectively. The effects of the amount of added modifiers on the waste liquid sensible heat of modified molten slag were studied during the modification process,which was subsequently confirmed by industrial test. It is indicated that the sensible heat of modified molten slag increases at first and then decreases with the addition of modifiers. The sensible heat improves with the increase in mass fraction of modifiers from 5% to 11% and reaches the maximum at the mass fraction of 11%. The optimal amount of modifiers ranges from 11% to 19% in consideration of both the utilization of sensible heat and the performance of modified molten slag. Furthermore,the industrial test verifies that both the fluidity of modified molten slag and the stability of cooled modified slag are significantly improved at the addition of about 12% modifiers.