Toxic cyanobacteria bloom in eutrophic, freshwater lakes and ponds has been reported world wide. The toxins produced by these organisms may cause environmental, health and recreational problems during or after the heaviest bloom. They potentially threaten human health and are increasing the worldwide interest in the health risk associated with cyanobaeterial toxins. The apparent increase in recent years of toxic blooms of cyanobacteria has stimulated extensive research on. The main purpose for the study described here was to investigate the environmental chemical behavior of microcystins in Lake Dianchi. The study of detoxification and utilization of the harvested biomass is also processed. This work is funded by the State Key Project "Cyanobacterial bloom control in Lake Dianchi", which is supported by State Commission of Science and Technology and the Govermnent of Yunnan Province. Microcystins are a family of more than 60 structurally similar hepatotoxins produced by species of freshwater cyanobacteria, primarily Microcystis aeruginosa.