Abstract: The physical and chemical properties of industrial desulfurizing slag and slag-conglomerating agent were studied in the present work.It was found that the desulfurizing slag has an exceptionally high melting temperature and is distributed widespread on the hot metal surface in granular forms, and industrial slag-conglomerating agent with high melting point and high viscosity.Therefore, it is difficult to remove desulphur ization slag by wiping of the slag from hot metal.In that case, resulphurization takes place in the LD process, especially in ultra-low sulphur steel production.According to the characteristics of industrial slag-conglomerating agent, slag-conglomerating agent with low meting point and high viscosity was developed.The results show that:the ratio is 2:5, which can be able to play a very good effect of conglomerating slag.