Abstract: To investigate the effects of exogenous nitrogen forms on the structure and function of rhizosphere soil microbial community, a field experiment was conducted using amplicon sequencing to analyze differences among five treatments: inorganic nitrogen as ammonium-N (T1) or nitrate-N (T2); partial substitution of inorganic nitrogen with organic nitrogen as amino acids-N (T3) or fulvic acids-N (T4); and a no-nitrogen control (CK). The results were as follows. (1) Nitrogen forms significantly affected the relative abundance of the three dominant phyla (Proteobacteria, Actinobacteria and Acidobacteria), as well as Gemmatimonadetes, Bacteroidetes and Firmicutes. (2) The Shannon index of nitrate-N was significantly higher than that of all other treatments, while the Chao1 and PD indices of ammonium-N and nitrate-N were significantly higher than those of amino acid-N, fulvic acid-N and CK. (3) Ecological network analysis revealed that partial substitution of inorganic nitrogen with organic nitrogen yielded rhizosphere microbial networks featuring smaller diameter, shorter average path length and higher clustering coefficient and density, with the rhizobial genus Aureimonas as the seed node of the core network. (4) FAPROTAX functional prediction revealed significant differences among nitrogen forms in chemoheterotrophy, photoheterotrophy, carbon metabolism, sulfur metabolism, nitrogen fixation and ammonification. (5) RDA analysis showed that only soil pH passed the Pseudo-test at the highly significant level (p<0.01), explaining 50.6% of the variation in rhizosphere soil microbial function. In conclusion, partial substitution of inorganic nitrogen with organic nitrogen could promote the formation of complex and tightly structured microbial ecological networks in rhizosphere soil, with the core network playing a positive role in plant growth promotion and disease resistance. RDA analysis revealed that variations in nitrogen forms drove changes in soil pH, which in turn shaped functional differences in rhizosphere soil microbial communities.