The invention provides a method for preparing tantalic chloride from titanium-tantalum enriched slag. The method comprises the following steps of uniformly mixing and charging Ta2O5-containing titanium-tantalum enriched slag and carbon powder into a chlorination furnace; performing chlorination reaction to generate mixed gas; passing the mixed gas through a dust collection chamber with the temperature being 180 to 200 DEG C; after the crystallization, collecting the materials into a dust collecting chamber to obtain a tantalic chloride coarse product; then, putting the tantalic chloride coarseproduct into the chlorination furnace; introducing chlorine gas to perform chlorination reaction; passing the gas generated after the chlorination reaction into the dust collection chamber with the temperature being 180 to 200 DEG C; collecting the tantalic chloride in the gas after the crystallization. The method provided by the invention has the advantages that the titanium-tantalum enriched slag is used as the raw materials; after the enriched slag chlorination, metal chlorides are obtained; by aiming at the boiling point differences of different used metal chlorides, the preparation of the tantalic chloride is realized; the technical advantages of low raw material cost, high product added value, simple and short flow process and the like are realized.