A laboratory experiment was conducted to study the effect of biochar and other amendments on soil enzymeactivities and soil microbial communitystructure,which was of great significance for rational application of soil amendmentsand evaluation of the effects of different amendments on soil fertility in upland red soil. Four treatments were used,which includedCK(control),Ca(calciumperoxide,1.72g/kg),C(biochar,21.46g/kg),C+Ca(biochar,21.46 g/kg,calcium peroxide,1.72 g/kg). Phospholipid fatty acid(PLFA)profiles for all treatments were used tocharacterize the microbial community structure. Soil microbial biomass carbon(MBC),dissolved organic carbon(DOC) and soil enzyme activities were also determined. The results showed that the amendments of biochar and calcium peroxideimproved the content ofMBC,DOC and the activities of soilinvertase(INV),amylase(AMY)andurease(URE), especially in combination with C+Ca. The average total PLFAs content of soil microorganism followed a decreasing order ofC+Ca,C,Ca,and CK. The relative abundance of soil bacteria was thelargest,accounting for 80% of the total microbialbiomass,followed byactinomycetes,which accounted for 13% to 15% of the total microbialbiomass,while the relative abundance of fungi and arbuscular mycorrhizal fungi was relatively low. Biochar and calcium peroxide improved the ratioof Gram-negativebacteria(GN)/ Gram-positivebacteria(GP),and that was the highest under C+Ca treatment. Principal component analysis of soil microbial PLFAs showed that adding biochar and calcium peroxide improved soilmicrobial community structure. The total score of principal components was calculated and combinedtreatment(C+Ca)had the highest comprehensivescore,which had the greatest influence on soil microbial community structure. Redundancyanalysis showed that soil MBC,DOC and soil invertase activities were all the main factors affecting the quantity andstructure of soil microorganisms. Therefore,biochar and calcium peroxide can significantly improve soil microbialbiomass,and improve soil microbial community structure and stimulate soil enzyme activities in upland redsoil,and the most significant treatment is combined treatment.