To meet the increasing demand of optical infrared telescopes and reduce the driving power， carbon fiber composite materials are used to carry out lightweight research on the main mirror truss of the telescope. The layout of carbon fiber composite truss element in the telescope's primary mirror chamber was optimized， and the evolution algorithm was used to select the optimal layout. The truss element of the telescope's primary mirror chamber was modeled， and the sensitivity analysis and evolution algorithm were used to select the best layup scheme. Three typical layup schemes were utilized for comparison. Static analysis and loading experiment are performed on the truss rod element. The six-bar triangular pyramid unit assembled by the rods is subjected to modal analysis and vibration test. The comparison of finite element analysis and experimental results show that the optimal layup plan is ［±45°/90°/0°/90°/0°］s. The equivalent axial stiffness obtained by the finite element analysis of the truss bar element of this scheme is 8.306×10⁶ N/m， and the experimental measurement is 7.463×10⁶ N/m； the equivalent radial stiffness obtained by the finite element analysis is 3 968.3 N/m， and the experimental measurement is 3 344.5 N/m. The modal analysis of the six-bar triangular pyramid element of this scheme shows that the first-order frequency is 93.699 Hz， and the first-order frequency is 84.683 Hz measured by the vibration experiment. The weight of the composite truss rod is 77.6% lighter than the steel structure of the same size， static and dynamic properties are better than steel rods of the same weight. The results of finite element analysis and experimental verification of the best layup scheme indicate that its static and dynamic properties are better than other schemes.