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.　©　2017,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.