Abstract: FL-1 bacterium was isolated from waste water,it had high flocculating activity. It was identified as Pseudomonas mendocina by 16 s DNA gel electrophoresis figure. Then single factor experiments were adopted to optimize the cultural conditions,including p H,arbon nitrogen source and temperature. At last,response surface analysis was used to optimize above mentioned four factors. The optimum culture conditions were determined as follows:initial p H of 7.0,glucose concentration of 26.5 g/L,(NH4)2SO4concentration of 0.5 g/L,cultivating temperature of 31 ℃. Under this culture conditions,the theoretical value of the flocculation rate was96.55%,and the test value was 95.19%. These results indicated that the experimental results were totally in accordance with the predictive results of response surface analysis which was a valid method to optimize the culture conditions of FL-1.