In this experiment, cysteine was used as an Oxidation Reduction Potential (ORP) adjustment to explore the responses of Microcystis aeruginosa (FACHB 469) under different ORPs'stimulation. A recovery experiment was also designed with M. aeruginosa separated from the former experiment and cultured in fresh medium. Results showed a negative effect of low ORP stimulation on the growth of M. aeruginosa. Within the range of -50 to -100 mV, inhibition effect was intensified with the ORP's decline. The uptake rate of phosphorus decreased under low ORP's stress but had no relationship with stress strength. A proper low ORP' s stimulation (e. g. -50 and -75 mV) could intensify the SOD enzyme activity of M. aeruginosa, while over low (e. g. -90 and -100 mV) had negative effects. M. aeruginosa could recover its growing ability after removing the lower ORP's stimulation. The uptake rate of phosphorus and the SOD enzyme activity returned to normal as well. Moreover, the enhancement of growth ability was observed by a low ORP's stimulation (e. g. -50 and -75 mV). Thus, the low ORP's stimulation had negative effect on the growth of M. aeruginosa, however the process can be reversible.