Cyanotoxins produced by cyanobacteria have caused pollutions in land surface water around the world.The most common toxin is microcystin(MC),a cancer inducing hepatoxin. No effective technology could be used to remove it up to now. Microbiulogical degradation should be a suitable way. In this study, we used BG-ll rnedium to culture Mi.crocystis nerngiraosa PCC 7806 in the library.MC was extracted by 70% methanol, then concenteafed and purified by C}fl solid-phase extraction collum. The relative contents of MC-LR and MC-RR were 68.2% and 9.3%, respectively, on the basis of high performance liquid chromatography(HPLC) analysis. We used this MG as seleraive substrate to isolate MC degradable bacaeria. From cyanobacterial bloom forming water body such as Xuanwu Lake,Qinhuai Rever, we got eighteen bacterial strains, which could degrade MC-LR obviously. The relafive efficiencies were from 18.4%to 48.2%.Five more effective strains of them were identified as rlcinetaLncter,Enterahacter, Microhacteriu.m, Bacillus and, Fratetcria, respectively by there morphology and biochemical characteristics. These strains were all different from the published ones up to now.