Abstract: By analyzing the morphology of wrinkle defects on the surface of large-sized cold heading steel wire rods, the causes of wrinkle formation were discussed. By optimizing the rough rolling pass and increasing the rolling start temperature,the deformation of the rough rolling 3#pass is reduced and the deformation temperature of the slab is increased, thereby improving the deformation of the metal at the corner of the slab and avoiding the generation of wrinkles. By reducing the deformation of the rough rolling 3#pass and increasing the rolling temperature, the maximum wrinkle depth of ML40Cr cold heading steel wire rod with a diameter of φ24 mm is reduced from 0.11 mm to 0.06 mm, and the cracking ratio of 1/3 cold top heading test is reduced from 35% to 4%.