Abstract: The effects on the growth of Anabaena flos-aquae were researched by Metsulfuron-methyl and Bensulfuron-methyl which are high activeness, effective and safe to animals. Visible Spectrophotography was employed to measure the Index of Absorbance which could be viewed as an index of the standing crop of Anabaena flos-aquae. The experimental results indicated that Metsulfuron-methyl and Bensulfuron-methyl have conspicuous effects of controlling algal growth and are more efficacious than Cupric sulfate. The inhibition on algae is closely related to the dosage and the initial algae cell density. The inhibition on algae is more evident with the increasing concentration of Metsulfuron-methyl and Bensulfuron-methyl and earlier exerting chemical reagents during the algae breeding. The higher amount of Metsulfuron-methyl or Bensulfuron-methyl is required with the rising of algae cell density. Furthermore, the inhibitory effect on algae is also obvious in small-scale body of water when the pure Metsulfuron-methyl and Bensulfuron-methyl were replaced by their solubility powder. These results proved the feasibility of applying the sulfonylurea herbicides to control the growth of algae and cure the increasingly serious pollution.