The invention provides a method for preparing building cementitious materials from ardealite by means of artificial quartzite slurry modification. The ardealite is industrial solid waste and is used as a main raw material for the building cementitious materials. The method includes drying and grinding the ardealite which is the industrial byproduct waste, uniformly mixing the ardealite, cement andindustrial byproducts such as slag powder and fly ash with one another to obtain mixtures, adding the mixtures into water and blending the mixtures and the water to obtain thick slurry; mixing silicafume with artificial quartzite slurry under high-speed stirring conditions and activating the artificial quartzite slurry; sufficiently mixing and homogenizing the thick slurry and the artificial quartzite slurry with each other, then adding polymeric aluminum and/or other aluminum salt and polycarboxylic acid water reducing agents into the thick slurry and the artificial quartzite slurry and uniformly stirring the polymeric aluminum and/or the other aluminum salt, the polycarboxylic acid water reducing agents, the thick slurry and the artificial quartzite slurry to obtain the plastic cementitious materials with short coagulation time and high strength and ardealite dosage. The silica fume is an industrial byproduct. The polymeric aluminum and/or the other aluminum salt are used as admixtures. The method has the advantages that the ardealite can be directly used after being dried and ground without earlier-stage purification and ageing treatment, accordingly, the production cycle canbe shortened to a great extent, and the cost can be reduced; the building cementitious materials are high in industrial solid waste mixing amount, the optimal industrial solid waste mixing amount canreach 80%, in other words, 80% of the traditional silicate cement can be replaced, and the method has important significance in saving resources, increasing the industrial solid waste comprehensive utilization rate and protecting environments.