For　PM2.5　pollution　investigation　in　China,　the　air　quality　modelling　system　WRF-CMAQ　was　applied　to　calculate　the　impacts　of　ammonia　emission　on　PM2.5　concentration.　The　results　indicated　that　ammonia　emission　had　the　biggest　contribution　for　secondary　nitrogen　particles,　with　annual　average　99.8%　for　nitrate,　99.7%　for　ammonium,　while　only　4.2%,　29.8%　for　sulfate　and　PM2.5　respectively.　Quantification　of　ammonia　emission　impacts　on　PM2.5　mass　concentration　were　also　conducted　in　January,　April,　July　and　October　as　representative　months,　counted　20.15μg/m3,　12.39μg/m3,　13.20μg/m3　and　14.20μg/m3,　respectively,　with　January　ranking　the　first　in　monthly　average　contribution.　It＇s　general　that　ammonia　emission　had　dramatical　influence　on　PM2.5　in　regions　where　agriculture　and　animal　husbandry　well　developed,　such　as　Henan,　Shandong,　Hubei　and　Hebei　province,　with　annual　average　contribution　all　exceeded　20μg/m3.　In　view　of　this,　ammonia　emission　control　will　lead　to　significantly　decrease　of　nitrate　and　ammonium,　therefore　reduce　the　PM2.5　pollution　level.　©　2016,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.