Abstract: Hollow carbon fiber was prepared from mesophase pitch by spining and carbonization at different temperatures. The cross section of the as-prepared hollow carbon fiber was observed by SEM. Effect of carbonization temperature on the electromagnetic performance of the hollow carbon fiber was studied by a bow testing system. The hollow carbon fiber carbonized at 900℃ has the largest electromagnetic energy loss. Effect of the laminate packing ways on the electromagnetic performance of composites was also investigated by the bow testing system. The eligible bandwith of composite is 10GHz and the maximum radar absorption is －25 dB when the carbon fibers are across packed.