The transmission spectra of the Nd:GGG crystal was analyzed. The particle inclusions in the Nd:GGG crystal were observed between crossed polarizers. The effect on the laser damage resistance of the absorptive colorcenter and the particle inclusions exist within the crystal was discussed. Through adopted appropriate growth technics, we achieved the Nd:GGG crystal without absorptive colorcenter and Iridium particle inclusions. The laser damage threshold reached above 2GW/cm2.