Abstract: 【Objective】 This study was conducted to investigate the effects of biogas slurry application on the coastal saline-alkali soil properties and the performance of ameliorated soil for agricultural production. 【Method】 Three annual vegetable crops were cultivated by using a biogas slurry in coastal saline-alkali land located in Dongtai, Jiangsu Province, with a total biogas slurry application of 0(CK), 65, 101, 138, 175, 211 and 268 m³/hm² for both pouring and spraying. The effects of soil improvement on agricultural production were verified by growing cauliflower. 【Result】 When the appropriate amount of biogas slurry was applied, i.e., soil pH value decreased from approximately 8.45 to 7.90, EC value decreased from approximately 478 μS/cm to 150 μS/cm, and organic matter content increased from approximately 65 to 268 g /kg. Total nitrogen content and available phosphorus content were also well maintained or recovered. Cauliflower grew well in ameliorated soil. In contrast to CK treatment, both yield and quality of cauliflower increased. Cauliflower yields under different treatments differed greatly. For pouring, the highest yield was 29 236.5 kg/hm² when 25.2 L per plot(84 m³/hm²)of biogas slurry was applied for a crop of cauliflower cultivation. Meanwhile for spraying, the highest yield was 23 628.0 kg/hm² when 31.2 L per plot(104 m³/hm²)was applied. Biogas slurry application could increase the contents of soluble sugar and Vc. 【Conclusion】 In general, the application of a biogas slurry can improve coastal saline-alkali soil properties, help to decrease soil pH and EC values, ameliorate soil acidity and alkalinity, and improve or restore soil fertility. Biogas slurry can be used for cauliflower cultivation in saline-alkali soil instead of conventional fertilizer. The effects of pouring are generally better than those of spraying, and the ideal amount of biogas slurry application ranges from 84-104 m³/hm² for a crop of cauliflower cultivation.