Abstract:In this paper, we used DGGE and Biolog to study the composition and function of soil microbial flora. Based on the UPGMA analysis, the results of the DGGE indicate that T1(CK) and T2(single inorganic fertilizer treatment) have a similarity of 41% in wheat season, T4（conventional NPK+ straw）and T5(conventional NPK+ straw + straw decomposing inoculants) have a similarity of 52%, and T3(70% conventional NPK + organic fertilizer) is clustered into one group alone. In corn season, the similarity between T1 and T2 is 68%, which is grouped into the first category, the similarity between T4 and T5 is 78%, which is grouped into the second category, and T3 as the third category. These results show that there are similarities between different fertilizer treatments. Through a series of experiments of gel cutting, sequencing and BLAST comparison, we find that most of bacteria in the tested soils is uncultured and the main cultured bacteria belong to Bacillus and Paenibacillus. Using principal component analysis, the results of Biolog show that T1 and T2 have similar microbial functions, and T4 and T5 also have similar functions, while T3 has different functions. Carbon source utilization characteristics of microbial communities have different results, T5 and T4 have the strongest metabolic function, and then T3 treatment, and T2 and T1 have the minimum. Our study suggests that the composition and function of soil bacteria have certain consistency under different fertilizer treatments.