Abstract: Cyanobacteria plays important role in harmful algal blooms, which not only threatens the industries, fisheries, tourism and ecosystems, but also affects public health due to the production of cyanobacterial toxins. Microalgal biomass is rich in proteins, nucleic acids and lipids and can be used as fertilizers,animal feed and biofuels through processing. It analyzes the cause and harm of alginization, the main source of nitrogen and phosphorus in surface water and the control technology, and discusses the utilization of algae.