Long-term excessive fertilization has caused soil acidification in paddy fields，and improving acidified soil is of great significance for increasing rice yield and promoting soil health. In the experiment，three fertilization treatments were set up:farmers’ conventional fertilization(FFP)，optimized fertilization(OPT)，and optimized fertilization + oyster shell powder + straw returning(SHM). The effects of different fertilization treatments on soil physical and chemical properties，bacterial community structure，and rice yield components were analyzed. The results showed that compared with FFP，both OPT and SHM treatments significantly increased soil pH and nutrient content，and reduced exchangeable acid and aluminum content. In terms of the soil bacterial community，the SHM treatment significantly enhanced soil bacterial diversity and altered the composition of the community structure. Compared with the FFP and OPT treatments，the SHM treatment significantly increased the relative abundances of Proteobacteria，Desulfobacterota，Firmicutes，and Spirochaetota，while the relative abundances of Acidobacteriota，Actinobacteriota，and Crenarchaeota decreased. At the genus level，the SHM treatment significantly increased the relative abundances of MND1，GOUTA6，Anaeromyxobacter，Spirochaeta，and Nitrospira，while the relative abundances of Candidatus_Nitrosotalea，Arthrobacter，Candidatus_Solibacter，Bryobacter，Acidibacter，Sphingomonas，HSB_OF53-F07，and JG30a_KF_32 significantly decreased. Redundancy analysis indicated that pH，exchangeable calcium，exchangeable acid，available potassium，and organic matter were the main environmental factors affecting the bacterial community composition. In terms of rice yield，the rice yields of the OPT and SHM treatments were significantly higher than that of the FFP，with increases of 2.95% and 10.23%，respectively. Correlation analysis showed that rice yield was significantly positively correlated with soil pH，soil nutrients，and bacterial diversity indices，and significantly negatively correlated with soil exchangeable acid and aluminum. Further analysis through the partial least squares path model(PLS-PM)found that soil pH，organic matter，and exchangeable acid were the main factors affecting rice yield and its components. In conclusion，the treatment of optimized fertilization + oyster shell powder + straw returning could effectively improve soil physical and chemical properties，optimize the microbial community structure，and increase rice yield，which was an effective acid reduction and fertility improvement management strategy.