The invention relates to a system and process for manufacturing a carbon fiber composite core of an electric transmission line. The invention is characterized in that the system comprises a yarn frame, a yarn-collecting board, a preheater, a double-roller constant-temperature replaceable glue tank, a glue-squeezing device, a primary preforming device, a carbon fiber preheating mold, a secondary preforming and coating device, a curing mold, a postheating oven, an air cooling device, a tractor and a winding machine which are sequentially connected, wherein a cloth guide frame is mounted above the secondary preforming and coating device, the carbon fiber preheating mold and the curing mold are respectively sheathed with a heater, and both sides of the carbon fiber preheating mold are provided with glass fiber yarn guide boards. In the preparation method provided by the invention, repeated experiments are carried out on the high-performance resin system, and the outermost layer is coated with the glass fiber cloth by fully considering characteristics of carbon fibers and high-strength glass fibers, thereby enhancing the transverse strength of the product, improving the cracking resistance of the product and realizing the feasibility of the process. Thus, the invention solves the problem that high-performance resin is difficult to pultrude.