Abstract: Dunaliella salina was irradiated with YAG, LD and Ar+ laser by different does as treatment does. After irradiated, the growth rate and pigment content of Dunaliella Salina were investigated to compare. The experimental results indicated that the cell multiplication and accumulation of β-carotenoid were inhibited by YAG laser, when the irradiation does exceeded one minute. LD laser accelerated cells' multiplication in 5～35 minutes irradiation does, the growth rate was increased most by 190 % in 5 minutes irradiation does. It also accelerated the synthesis of chlorophyll and the accumulation of carotenoid in 5 minutes irradiation does, and the pigment content were increased most by 27.2 % and 24.4 % respectively. Carotenoid was accumulated in 5 minutes～30 minutes irradiation does by Ar+ laser, compared with the comparision group, the content was increased most by 18.5 %～130.9 %, but the synthesis of chlorophyll was inhibited. The lecture has discussed the primary study on biological effect of Dunaliella salina by different laser.