Abstract: Soil fauna is one of the most important indicators in soil ecosystem.For defining effect of long-term fertilization on soil fauna diversity,the relationship between long-term fertilization and farmland soil animal diversity was studied at long-term fertilization area of Black soil in Northeast China.Three long-term fertilization treatments were carried out in this study including no-fertilizer(NF),chemical-fertilizer(CF) and chemical fertilizer with addition of pig manure(CMF).Modified Tullgren method was used to extract soil fauna from 0~15 cm soil depth.1 800 individuals were extracted totally,all of them belong to 27 families.The dominant families were Liodidae,Sejidae and Oribatellidae.The individual number and the richness index were significantly different among three fertilization treatments(p<0.05),while the difference of community number,diversity index and the evenness index among fertilization treatments were not significant.The diversity of the soil fauna in the farmland was related to fertilization treatments.The stable soil fauna community was benefited from the organic manure application which can better protect the environment of agro-ecosystem than chemical fertilization.