Taking partial denitrification sludge as seeding sludge, which could reduce nitrate (NO₃^--N) to nitrite (NO₂^--N) with stable NO₂^--N accumulation. NO₂^--N accumulation properties of partial denitrification with different carbon nitrogen ratio (C/N), NO₃^--N and pH were studied by batch experiments with methanol as carbon source. The results showed that C/N had no significant effect on the maximum accumulation of NO₂^--Nor specific denitrification rate when C/N was 2.5~5. When C/N was 2.5, NO₂^--N accumulation rate was 89% and NO₂^--N was not reduced. But when C/N>3, NO₂^--N would be reduced after NO₂^--N accumulated to the maximum value. In the case of C/N was 2.5 and NO₃^--Nwas 14.96~58.71mg/L, specific denitrification rate increased with the increase of NO₃^--N. Continue to improve NO₃^--N, the change of specific denitrification rate was very small. On the other hand, when NO₃^--N>29.01mg/L, the higher NO₃^--N was, the lower C/N required. PH had a significant effect on the maximum accumulation of NO₂^--N and the specific denitrification rate in the partial denitrification process. When pH=7, NO₂^--Naccumulated rate、specific NO₃^--N reduction rateand specific NO₂^--N accumulation rate was 24.49mg/L、18.96 (mg/(gVSS·h))、18.91 (mg/(gVSS·h)). And then followed byp H=6、8、9. When pH=5 and 10, the partial denitrification process could not be carried out. This study could provide a theoretical basis for the realization and application of partial denitrification.