Abstract: One facultative oligotrophic bacteria 9B was isolated and screened from the different water samples around Nanyang Medical College to measure the change of CODMn in minor-polluted water and check organic degradation extent of the strain in polluted water. The results showed that the COD Mn degradation rate of the strain 9B in minor-polluted water reached 81.25% in seven days. Water became more transparent than that prior to disposal. The starvation resistance experiment revealed the strain can long live under low-nutrient conditions.