To further explore the differences in the effects of raw materials and pyrolysis temperature of biochar on soil microorganisms, an open-air pot culture experiment was used, in which maize straw biochar and rice straw biochar made at pyrolysis temperatures of 350, 550, and 750 ℃ were added to paddy soil for 60 days and 360 days, respectively, and the Illumina Novaseq technique was used to analyze their impacts on the diversities and community structures of bacteria and fungi, as well as differential microorganisms. The results showed that both types of biochar cultured for 360 days improved the richness and diversity of bacteria in paddy soil, with rice straw biochar showing the most significant improvement. The dominant groups of bacteria in soil were Planctomycetes, Chloroflexi and Actinobacteria. With the extension of biochar culture time, the richness and diversity of fungal communities in soil showed a trend of first decreasing and then increasing. The dominant fungal groups in soil were Ascomycota and Basidiomycota. After 360 days of cultivation, the species richness at fungal family level was more uniform, and Chytridiomycota and Mucoromycota were commonly detected in soil. After 60 days of cultivation, corn straw biochar at 550℃ pyrolysis temperature had the best effect on improving the richness and diversity of bacteria and fungi. The addition of rice straw biochar at different pyrolysis temperatures led to different dominant categories of fungal community, changing the structure of soil microbial community. In conclusion, in paddy soil, compared with corn straw biochar, rice straw biochar has a better effect on improving soil microbial diversity after 360 days of application. The type of biochar raw material is an important factor affecting soil microbial diversity, and pyrolysis temperature can affect microbial community structure, especially the influence of rice straw biochar pyrolysis temperature on fungal community structure.