The invention discloses a heat treatment processing method for eliminating the mixed crystal defect of 30CrNi3MoV alloy steel and belongs to the technical field of alloy steel processing. According tothe heat treatment processing method, firstly, forging is conducted by the adoption of an existing forging technology; then, heat treatment processing is conducted on the forged forge piece, the normalizing and quenching temperature and heat preservation time of the 30CrNi3MoV alloy steel are controlled and improved, structure inheritance is eliminated through fabrication processing, and a good mixed crystal defect eliminating effect is achieved. By the adoption of the heat treatment processing method for eliminating the mixed crystal defect of the 30CrNi3MoV alloy steel, the inner structureof the workpiece can be effectively improved, the mixed crystal and coarse crystal particle defects are reduced, the material mixed crystal defect is eliminated, and the yield of the workpiece is improved.