In order to study the effect of biogas slurry replacing nitrogen fertilizer on soil properties and crop yield of lightly salinized fluvo-aquic soil, a corn field experiment was carried out on lightly salinized fluvo-aquic soil in Yangxin County, Binzhou City. Four treatments were set up in the experiment, which were conventional fertilization (XG), biogas slurry replacing 50% (T50), 70%(T70) and 100% (T100) of conventional fertilization nitrogen.The results showed that compared with conventional fertilization, the contents of soil alkali-hydrolytic nitrogen, available potassium and organic matter were significantly increased by 32.30%-34.29%, 27.37%-72.25% and 14.96-21.09%, respectively. T100 treatment was more beneficial to increase soil organic matter content. T50 treatment had the best effect on soil available phosphorus and available potassium. T50 and T70 treatments significantly increased the contents of Fe, Cu, Zn. T50 treatment could not significantly increase the content of Hg, Cd, Cr, Pb and soil conductivity. Replacing nitrogen fertilizer with biogas slurry significantly increased soil alkaline phosphatase and sucrase activities by 7.1%-32.6% and 17.4%-19.8%, respectively. Biogas slurry instead of nitrogen fertilizer treatment significantly increased microbial richness. Compared with XG treatment, T50, T70 and T100 treatments significantly increased corn yield by 19%, 16.8% and 18.7%, respectively. Comprehensive analysis showed that replacing nitrogen fertilizer with biogas slurry of different proportions could significantly improve soil properties and increase corn yield, and applying 50% biogas slurry on the basis of conventional fertilization had the best effect. The research results can provide theoretical reference for the application of biogas slurry onlightly salinized fluvo-aquic soil.