With the help of finite element analysis software Deform-3D, the defect reason of initial cold-extruded technology scheme for sprocket of silent chain was obtained by numerical simulation. The reason is that metal flow is unreasonable and max principle stress exceeds the material's tensile strength 885MPa. In order to solve this problem, improved technology of extrusion forming with reducing diameter was proposed that reduced the diameter before forming the tooth profile. The numerical simulations show that the improved cold-extruded parts achieve full gear teeth and max principle stress is less than the material's tensile strength. At last, the technological tests show that the improved technology scheme of cold-extrusion avoids the extrusion defect and the cold-extruded parts are of good quality.