Adopting a copper vapor laser system consisting of a self-filtering unstable resonator and an inject ion-locked amplifier, the output power of 9.2 W on 510.6 nm line with polarization degree of 93% and about six times as large as diffraction- limited divergency was obtained. Focusing the laser beam into a 9 mm long BBO crystal, the second harmonic of 1.2 W was generated with conversion efficiency of 13%. When the filtering aperture was removed, the conversion efficiency fell down to 8%.