The efes of biogas slurry combined with chermical frilizer on soil microbial characteristies, soil nutrients and maize growth were studied. The results showed that biogas slurry combined with chemical fertilizer and biogas slurry alone reduced the number of soil funpi and increase the number of bacteria and actinomycetes. The number of funpi in 45% biogas .slury combined with 55% chemical fertilizer treatment was signifceantly lower than that in conventional ferilization by 66%，and the number of bacterin and actinomyceles was significanly increased by 160.3% and 312.5%，respectively. Biogas slurry combined with chemical fertilizer significantly increased soil urease, phosphatase and invertase activities, but the change of catalase content was not obrious. The appication of biogas slurry efectively promoted the increase of soil organic matter,total nitrogen, total phosphorus, akalilydrolyable nitrogen, available phosphorus and available potassium, and the dferences were significant. Soil microbial biomass ( SMB ) and organie carbon ( S0C ) were fectively increased by biogas slurry combined with chemical frilizer. Compared with conventional friliatin, 45% biogas slurry combined with 55%chemical ferilizer significantly increased soil micobial biomass carbon ( SMBC)，microbial biomass nitogen ( SMBN), microbial biomass phosphorus ( SMBP ) and organic carbon (S0C )by 70.0%，195.6%， 91.6% and 71.6%，respectively.The application of biogas slurry decreased the MBCMBN ratio, while soil microbial entropy ( qMB ) and soil MBN/TN value increased, and inereased first and then decreased with the inerease of biogas slurry dosage. Correlation analysis showed that soil SMB was signifcantly or extremely significantly positively correlated with soil organie matter, total phosphorus, akali-hydrolyzable nitrogen, available phosphorus and available potassium. Urease, phosphatase and sucrase were significantly or ecxtremely significantly poaitively corrclated with soil nutrients， and catalase was not signifcantly corelated with soil nutrients. The applieation of biogas slury combined with chernical frilizer significanly promoted the growth and pholosynuhesis of maize, and the treatment of 45% biogas sluy combined with 55% chemical frtilizer was the bhest. With the increase of biogas slury proportion, the yield of maie increased first and then decreased. The treatment of 45% biogas slury combined with 55% chemical frilizer was the highest, which was significantly increased by 40.9%，compared with conventional frtilization. Comprehensive analysis showed that 45% biogas slurry combined with 55% chemieal frtilier could eectively improve soil strueture, significanly improve soil frtiliy, thereby promoting crop growth and increasing yield, which could be used as the optimal proportion of biogas slurry combined with chemical fertilizer.