The invention provides a preparation method of impregnant for a compacted anode carbon block. The preparation method comprises the following steps of 1, mixing coal pitch with solvent at the temperature of 80-135 DEG C, so that a coal pitch solution is obtained, wherein the solvent comprises wash oil and kerosene; 2, conducting centrifugal separation on the coal pitch solution, and conducting reduced pressure distillation on obtained supernatant liquid; and 3, mixing a product of the reduced pressure distillation with nanometer carbon powder, so that the impregnant for the compacted anode carbon block is obtained. The QI value of the prepared impregnant for the compacted anode carbon block is low, so that in the impregnation process, the impregnant can be excellent in flowability and permeability; the impregnation effect of the impregnant is enhanced; and after an impregnation roasting process is completed, the porosity of an anode is effectively lowered. Meanwhile, the obtained impregnant for the compacted anode carbon block is high in coking capacity value; reinforcing and filling of the anode carbon block are achieved; and electrical conductivity and mechanical strength achievedafter the anode carbon block is roasted are effectively improved.