At low temperature (400° C), chemical vapour deposition (CVD) is employed to make comb-like Co-doped ZnO nanocantilever arrays (NAs). The magnetization curves of the as-synthesized Co-doped ZnO NAs indicate the existence of above-room-temperature ferromagnetism (ARTFM) (Curie temperature, Tc > 300 K) whereas un-doped ZnO NAs does not. The corresponding ferromagnetic source mechanism is discussed, in which defects play an important role due to the strong green light emission.