Abstract: The effects of different concentration additives A and B on the phytoplankton growth were studied.The results indicated that additive A had significant effect on the growth of phytoplankton, and additive B had no, and there was not significant interaction between additive A and additive B.When additive B was 0.032 gm-3and A was 0.24 gm-3, the combination effects were the highest for the first selection; Through further selection toward the additive A, it was the best in the concentration of 0.28 gm-3.Microscopic analysis showed that Bacil-lariopkyta and Chrysophyta were preponderant algaes.