On the basis of carbon fiber composites with advantages of high specific strength and high modulus, a structural design scheme of the carbon fiber composite primary force-taking structure combined with several layer element modules was proposed for a principle bearing cylinder in satellite and rocket structures. A primary force-taking structure was designed based on composite laminate structure theories and section beam theories. The designed primary force-taking structure was molded in layering by carbon fiber composite material piles to remove the couple stiffness between the layers and was formed with a thin skin+“几”stringers +”T”-shaped cross-rib truss structure to improve its loading abilities. The primary force-taking structure was simulated numerically. The results indicate that the strength and stiffness of the designed structure meet design requirements. Finally, the primary force-taking structure was assessed by experiments. The verified results show that both the experimental results and simulation results are consistent. As compared to the same type of aluminum structure, the deadweight of the designed structure has reduced by 30%, which means that the proposed lightweight design method is effective.