In order to improve aggregate structure of urban soil, the effects of single application of food waste biogas residue composting (BRC), chemical amendment (CA) and mixed application of BRC and CA on the formation of soil water-stable aggregates and their structures were studied in a typical relocation site in Shanghai by outdoor cultivation experiments. The results showed that 20% and 30% BRC significantly increased large aggregates of 0.5-1.0 mm and 1.0-2.0 mm diameters and micro-aggregates of 0.106-0.25 mm diameter in relocation site (P<0.05), while significantly decreased micro-aggregates of <0.106 mm diameter (P<0.05). β-cyclodextrin increased the total amount of micro-aggregates significantly (P<0.05). 3 kg/m³ calcium sulfate and ferric oxide significantly promoted the formation of large aggregates (P<0.05). The combined application of BRC and CA significantly increased large aggregates of >2.0 mm and 0.25-0.5 mm diameters (P<0.05), but decreased micro-aggregates of <0.106 mm diameter compared with the single application of BRC or CA (P<0.05). On the improvement of aggregate structure, 20% BRC had the best effect in BRC treatments, while 3 kg/m³ calcium sulfate had the best effect in CA treatments, followed by 3 kg/m³ iron oxide, while WG₂₀+SM_mix (20% BRC+1 kg/m³ of β-cyclodextrin, calcium sulfate and iron oxide, respectively) had the best effect in the combined BRC and CA treatments, whose aggregate structure reached 19.03%, increased by 94.0%, 73.5% and 26.0% respectively compared with CK (100% soil), SM_mix (1 kg/m³ of β-cyclodextrin, calcium sulfate and iron oxide, respectively) and WG₂₀ (20% BRC).