Aiming at the question of selenite microorganism reduction with a long reduction time. The impact of different redox mediators (α-AQS,AQS,1,5-AQDS and AQDS) on selenite reduction by Shewanella oneidensis MR-1 was investigated. Optimizing culture conditions by single-factor experiment. Characterization the Zeta potential and average diameter. Results show that all of the redox mediators(α-AQS,AQS,1,5-AQDS and AQDS) is able to accelerate the reduction of selenite by Shewanella