To determine the influence of longterm application of fertilizers on the nitrification and ammoniaoxidizing microorganisms in neutral purple soil,chemical analysis and realtime PCR were employed and effect of different fertilization on the microbial abundance.Results showed that the amoA gene copy numbers of ammoniaoxidizing archaea(AOA)was obviously higher than that of ammoniaoxidizing bacteria(AOB)in purple soil and effect of fertilization on AOA was slight.Both N and P application improved the abundance of AOB,and the highest population sizes of AOB appeared in the 1.5NPK+M treatment.Compared with no chloridefertilizer treatments,the abundance of AOB and nitrobacteria for treatments with chloridefertilizer were decreased by 3.74% and 88.12%. Longterm fertilization resulted in change of the abundance of AOB,and organic fertilizer combined chemical fertilizer application improved the soil ammonia oxidation potential and nitrification ability.