In this work, to study the characteristics of carbon fiber-reinforced composites with different fiber cross-section types, such as round, C, and hollow-shape, the thermal conductivity and mechanical properties were investigated and compared. The thermal conductivity was measured by means of steady-state method to the parallel and perpendicular direction of reinforcing fibers. The mechanical properties were evaluated by a variety of test methods i.e., flexural, interlaminar shear strength, and impact strength. As a result, it was found that the thermal conductivity was greatly depended on the cross-section type of the reinforcing fibers, as well as, the reinforcing orientation. Especially, the anisotropy factor (k(//)/k(perpendicular to)) and the thermal diffusivity factor (alpha(//)/(perpendicular to)) of C and hollow-type carbon fiber-reinforced composites showed about two times higher values than those of round-type one. Also, the mechanical results showed that C and hollow-type carbon fibers-reinforced composites had higher values than those of round-type one in all mechanical tested. These results were probably due to the basic properties of non-circular (C and hollow-type) carbon fiber which can improve interfacial binding forces and widen interfacial contact area between reinforcement and matrix, resulting in effectively transferring the applied stress.