Abstract: Soil nitrification was studied with the coffee planting soils from Mangshi and Lujiangba, major producing area of Yunnan Province. To study nitrification and influencing factors, 5 coffee planting soil samples were collected. An incubation experiment was conducted to analyze the effects of soil properties and characteristics of ammonia oxidation microbial on nitrification. The result showed that the net N nitrification rates were 1.83−7.42 mg·kg⁻¹·d⁻¹ in a 0−7 days incubation experiment. The soil pH value was important factor for the net nitrification rates, which were positively correlated with pH (p<0.01). Higher net N nitrification rates reduced soil pH values and were responsible for the soil acidification in experimented acid soils. In the test soil, numbers were noticeably higher for ammonia-oxidizing archaea than for ammonia-oxidizing bacteria, suggesting that the relative abundance of Candidatus nitrosotalea (group I.1a-associated ammonia-oxidizing archaea) was the highest in all soil ammonia oxidizing microorganisms and nitrite oxidizing bacteria. There was no significant correction between relative abundance of Candidatus nitrosotalea and net N nitrification rates, while net nitrification rates were positively with the olsen-P (p<0.01) and available-K (p<0.01). As result of strong nitrification with high pH value, ammonium nitrogen is nitrified into nitrate nitrogen, which is readily accumulated and/or soil acidification. It is, therefore, essential to regulate soil buffer capacity to a proper level so as to achieve the target of constructing a nitrogen nutrient pool and reducing.