Abstract: Taking fertilization group (F) and no-inoculation-fertilization group (CK) as control, soybean were inoculated when sowing with Glomus mosseae (GM) and Glomus intraradices (GI) respectively, the impact of arbuscular mycorrhiza (AM) fungi on soybean biomass, the amount of soybean rhizobium, soil enzyme activity and so on were investigated to further reveal the influence of AM inoculum on crops in field. The results showed that, soybean could be colonized by and form mycorrhiza with both the two AM fungi strains, of which the colonization percentage with GM inoculation was up to 86.6% of the highest, while 78.3% with GI. And both the two AM fungi could dramatically elevate soybean biomass by 7.38% with GM and 3.88% with GI inoculation compared to CK. In addition, the amounts of soybean rhizobium with AM fungi inoculation exceed significantly the two control groups as well, suggesting AM fungi could promote root nodule formation which in turn enhanced soybean nitrogen-fixing ability. Beside, the activities of soil catalase and urease increased significantly with AM inoculum addition and reached their top at branching stage. However, fertilization had a certain inhibitory effects on soil urease activity decreasing its activity in soil, while had no significant effect on soil catalase activity.