Abstract：The RS strain, Nocardia sp., was screened at extreme cultivation conditions to improve the acrylamide- tolerance of nitrile hydratase. Arylonitrile was fed periodically into the shaker containing the RS cells and medium to produce acrylamide by the cells. The extreme cultivation conditions were formed by gradual accumulation of acrylamide. The acrylamide-tolerance of cells was enhanced in the coupling process of cell growth, enzymatic catalysis and screening. The survival rate, specific death rate and nitrile hydratase activity of cells as the function of acrylamide concentration during the process were investigated. The amount of living cells decreased rapidly with the increase of acrylamide concentration and the survival cells were cultivated on solid medium to gain a new strain RS-1. The average reaction rate of acrylonitrile hydration catalyzed by the RS-1 cells was 30.8% higher than that by the RS cells within 0~400 g/L of acrylamide concentration. Accordingly, the acrylamide-tolerance of nitrile hydratase in the RS-1 cells was superior to that in RS cells. Under the same conditions, the hydration processes catalyzed by the RS and the RS-1 strain were compared. The final acrylamide concentration and percent conversion of acrylonitrile in the hydration catalyzed by the RS-1 strain were 587.1 g/L and 99.97% respectively, which were higher than those by the RS strain significantly. In the further study on acrylamide production catalyzed by the RS-1 strain, the final acrylamide concentration reached 641.4 g/L.