Abstract: The present study investigated the tolerance of Microcystis aeruginosa PCC7806 (Ma 7806) to Cr⁶⁺ at 20℃ and 30℃, and measured the removal efficiency of Cr⁶⁺ by Ma 7806. The results showed that with increasing the concentration of Cr⁶⁺, the inhibition on the growth rate and chlorophyll a (Chl a) biosynthesis of Ma 7806 became stronger, but the biosynthesis of extracellular polysaccharide significantly increased. The biological synthesis content of extracellular polysaccharide at 30℃ was significantly more than that at 20℃ (P <0.05). The removal efficiency of Cr⁶⁺ by Ma 7806 reached the maximum when the concentration of Cr⁶⁺ reached 0.6 mg/L, namely 84.7% at 20℃, 98.3% at 30℃, respectively. The adsorption capacity of Cr⁶⁺ by Ma 7806 reached the maximum when the concentration of Cr⁶⁺ reached 9.0 mg/L, and the maximum adsorption capacity were 39.3 g/g at 20℃, 58.6 g/g at 30℃, respectively.