A multi-element activator of raw materials used in producing cement with vertical mechanical kiln contains waste steel dregs of converter (20-65 wt.%) with basicity of (2.4-4.8), fluorspar (5-25) with calcium fluoride higher than or equal to 45%, and gypsum (30-50) with SO3 content higher than or equal to 30%. It is prepared through uniform mixing. Its advantages are no need of correcting material, easy control, high strength of clinker, high outtput of kiln,low energy consumption and low cost.