Abstract: Growth method is the dominating factor which greatly influences the growth and the laser damage threshold of the DKDP single crystal. In this paper, DKDP crystals were grown from 85%-deuterated solution by using traditional temperature-reduction method and point-seed rapid growth method respectively. Optical transmission and laser damage in unconditioned type Ⅱ tripler-cut DKDP crystals have been studied. It is found that, due to super-saturation effect, by using point-seed rapid growth method, the growth rate of DKDP is about 15 mm/day, which is ten times that by using traditional growth method. But more metallic ionic impurities and inclusions lead to the deterioration in the transmission spectra and laser induced damage threshold.