A design of dual diodes pumped Nd∶YVO4 crystal , I-typed critical phase matching LBO crystal intra-cavity frequency doubled green laser at 532nm with Z2shaped cavity was described in the paper. Under the condition of 3. 12W incident pumping power ,green laser output of 670mW with TEM00 mode was obtained at last . Measurements showed the long-term stability in 4 hours better than 3 % ,polarization rate more than 500∶1 ,and amplitude fluctuation less than 0. 5 %.