The invention discloses a preparation method of a high-strength anti-corrosion bolt. The preparation method comprises the following processing steps of: a, casting a rod material which comprises the following chemical components according percentage composition: 0.4%-0.8% of C, 0.02%-0.05% of Si, 0.18%-0.21% of Mn, 0.16%-0.18% of P, 0.05%-0.07% of S, 0.05%-0.15% of Cr, 0.05%-0.12% of Ti, 0.11%-0.13% of Cu, 0.01%-0.02% of Al, 0.02%-0.03% of Mg, and the balance of iron; b, performing acid pickling on the casted rod material, performing wire drawing on the rod material according to the wire diameter requirement of the bolt so as to shrink the rod material to the wire diameter required for the bolt, cutting the rod material with the shrunk wire diameter to a length required for the bolt, placing the cut rod material in a die cavity at a normal temperature, and shaping the rod material to be in the size of the head part and the rod part required for the bolt through forging force. By processing the bolt through the cold extrusion process, the preparation method of the high-strength anti-corrosion bolt provided by the invention has the effects of improving the strength of the bolt, ensuring that the hardness value and the strength value required for a 12.9 high-strength bolt are achieved, and solving the problems of delay fracture and fatigue fracture of the bolt under high strength; and the bolt is reliable for connection and less prone to breaking in use, the service life of the bolt is prolonged, and thus the use requirement on high-strength bolts in various industries in society is satisfied.