The present invention relates to carbon fiber composites and a method for producing the same. By reducing specific transition metal ions with a specific concentration, the method for producing the carbon fiber composites can form nanoparticles of a transition metal on an outer surface of a titanium dioxide layer encapsulating a carbon fiber to produce the carbon fiber composites. The nanoparticles of the transition metal directionally contact the titanium dioxide layer, so that the carbon fiber composites have synergistically photocatalytic activity.