We studied the temporal, spatial, energy and polarized properties of a copper vapor laser with plane-plane resonator into which a parallel polarized beam was injected. The results showed that comparing with the original oscillator , the output of such injection-locked copper vapor laser was increased by 43%, the degree of polarization risod from 0.30to 0.78, the pulse width was broadened from 36ns to 48ns, the divergence of output beam was improved remarkably from 7.8 mrad to 1.1 mrad and approximately equal to that of the injecting beam.