Abstract: Take PBT/PP/30%GF plastic head for an example, difficulties in mold design were analyzed.Resin pouring system,sheave guide are core pulling structure ,thread demoulding structure and wire cylinder needle with two-setp ejection mechanisum were designed.The overall sructure and working process of the mould were introduced.The mold without external pulling device can achieve plastic parts are core pulling by the injection molding machine itself.