The invention belongs to the field of comprehensive utilization of metallurgical resources and specifically relates to a method for preparing titanium carbide through carbon thermal reduction of titanium-contained blast furnace slag. The method comprises the following processing steps: (1) fine grinding; (2) material mixing; (3) reduction; (4) cooling; (5) acid leaching; (6) standing stratification; (7) washing with water and drying, so as to obtain the titanium carbide finally. The method has the highlights that a boron-contained compound is added for carbon thermal reduction, and acid leaching and standing stratification are performed on a reduction material, so that calcium, magnesium, aluminum, silicon, ion and the like in titanium and furnace slag are separated. According to the method, the problems of low extraction rate of titanium, low comprehensive utilization rate of the resources and the like existing in comprehensive utilization of the titanium-contained blast furnace slagcurrently are solved; the method has the advantages of being simple in process and high in extraction rate of the titanium, being environmentally friendly and efficient, etc. The prepared titanium carbide has excellent properties of high temperature resistance, abrasion resistance, high hardness and the like, can be widely used in high-grade, precision and advanced industries of aerospace, abrasion resistant refractory materials, alloys and the like, and has huge economic benefits.