Resisting densification of hollow fiber support layers under high-temperature pyrolysis is critical to form carbon molecular sieve hollow fiber membranes with thin separation layer and attractive productivity. In this paper, a new silica particle stabilization approach is introduced to form thin-skinned composite carbon molecular sieve hollow fiber membranes with excellent resistance to support layer densification. By dispersing small-sized silica particles with low bulk density in the support layer of polymer precursor hollow fibers, composite carbon molecular sieve hollow fiber membranes were formed with highly porous supports. The composite carbon molecular sieve hollow fiber membranes showed very attractive selectivities and productivities higher than those of monolithic asymmetric carbon molecular sieve hollow fiber membranes formed by the standard sol-gel support stabilization technique.