An efficient, rapid multiplicative, stable and safe nitrite-degradating strain was selected from aquatic water. According to the conventional physiological, biochemical measurement and the 16S rRNA sequence analysis, the strain was identified as and named SZ-3. Based on the single-factor optimization tests to the strain, the optimum degradation conditions are found as follows, the optimal pH value is 7, the perfect temperature is 33 and the minimum glucose require ment of degradation is 0.01 mg/L. Under these circumstances, the degradation rate of SZ-3 strain to nitrite came up to 69.58% in 24 h. In breeding test of 100 L polluted water in which the concentration of nitrite is 5 mg/L, the degradation rate of SZ-3 strain on the nitrite achieved at 91.78% for 96 h in 28of SZ-3 which was obtained by centrifugated 1 CFU/mLl) culture fluid. All of these tests above indicate that the strain can degrade the nitrite in polluted water efficiently.