Taking the typical relocated site soil in Shanghai as the research object, the effects of single and mixed application of food waste biogas residue composting and chemical conditioner (Beta-cyclodextrin, Calcium sulphate, Iron(III) oxide) on soil physical and chemical properties were studied, and the soil quality of each treatment was evaluated comprehensively in order to explore the best soil improvement formula. The results showed that biogas residue composting significantly reduced soil bulk density, improved soil capillary porosity, total porosity, saturated water capacity, field water capacity, infiltration rate and other physical properties (P<0.05), significantly reduced soil pH, improved soil electrical conductivity, organic matter, hydrolytic nitrogen, available phosphorus and available potassium. With the increase of the application amount of biogas residue composting, the improvement effects on soil physical and chemical properties were more significant (P<0.05), and the improvement effect of combined application of 20% biogas residue composting and 3 kg/m³ chemical conditioner was significantly better than that of 20% biogas residue composting alone and 3 kg/m³ chemical conditioner alone (P<0.05). Compared with CK (without biogas residue composting and chemical conditioner), other treatments all promoted soil quality, and the comprehensive score of soil quality evaluation was as follows: 30% biogas residue composting treatment > 20% biogas residue composting and 3 kg/m³ chemical conditioner treatment > 20% biogas residue composting treatment > 10% biogas residue composting treatment > 3 kg/m³ chemical conditioner treatment, therefore, 30% biogas residue composting is recommended for application due to its best effects in soil improvement.