Abstract: Taking the 3D printing products of continuous carbon fiber reinforced PLA composite (CCFRC/PLA) as the research object, a flexible wire feeding mechanism of continuous carbon fiber reinforced PLA composite (CCFRCF/PLA) was designed The relationship between the expansion characteristics of the resin coating on the surface and the height of the printing layer is discussed. The influence of the nozzle end diameter on the thermal radiation of the printing surface is discussed. The calculation formula of the nozzle diameter is derived, and the optimal nozzle diameter and the optimal end diameter are solved. Based on the designed print nozzle, the relationship between the print layer height and the mechanical properties of the fabricated part was explored by using experimental verification and simulation analysis, and the results showed that the tensile strength of CCFRC/PLA was positively correlated with the number of fiber layers, which verified the validity of the laminate prediction model. And the correction coefficient of the tensile strength of CCFRC/PLA is 0.039 for printing layer height of 0.1 mm and 0.124 for printing layer height of 0.2 mm, which provides a theoretical basis and reference value for the development of continuous carbon fiber reinforced composite 3D printing technology.