In order to elucidate the application potential of high nitrogen organic material of Myriophyllum aquaticum in agricultural biology，this study conducted a pot experiment using Myriophyllum aquaticum straw as a partial substitute for chemical fertilizer nitrogen，examining the effects of different proportions of Myriophyllum aquaticum on soil fertility improvement and crop growth.The results showed that partially replacing chemical fertilizer nitrogen with Myriophyllum aquaticum straw effectively increased soil nutrient content.Compared with conventional fertilization treatment，replacing 10% inorganic N fertilizer with Myriophyllum aquaticum straw significantly increased the contents of organic carbon，total nitrogen and soluble total nitrogen in soil by 1.7%，3.9% and 76.7%，respectively.Replacing 30% inorganic N fertilizer significantly increased soil ammonium nitrogen content by 76.7%.Concurrently，the activity of soil sucrase，acid phosphatase and microbial biomass nitrogen content were significantly elevated by 3.5%，7.9% and 85.7%，respectively，compared with NPK treatment.However，straw 20% N substitution effectively increased urease，microbial biomass carbon and biomass entropy，with respective increases of 10.6%，24.6% and 25.0%，respectively.Moreover，the replacement of N 30% by Myriophyllum aquaticum straw significantly affected the growth of rice，compared with NPK treatment，the total biomass and aboveground biomass of rice plants increased by 39.9% and 41.4%，respectively.Correlation analysis also showed that soil microbial carbon content，microbial entropy and ammonium nitrogen content were significantly positively correlated with crop biomass (P<0.05)，while soil sucrase and microbial biomass carbon were significantly positively correlated with crop biomass (P<0.01).In summary，the application of 30% Myriophyllum aquaticum straw instead of inorganic fertilizer measures，compared with other treatments，significantly improved soil fertility while also significantly increased crop biomass，thereby promoting the sustainable development of rice production.