[Objective] We investigated the effects of different proportions of garden waste compost and bentonite for improving coastal saline soil. This was in order to formulate suitable amendments for solving the problems of high soil salinity and poor ecological environments in coastal areas.[Methods] Through field trials in a coastal area, changes in soil enzyme activity, microbial biomass carbon, and nitrogen in different treatment groups were measured, and their correlations with soil physical and chemical properties were analyzed. This was achieved by applying 68 kg/m³ compost garden waste (T₁) alone, 15 kg/m³ bentonite (T₂) alone, and a mixed application of compost garden waste and bentonite (T₃).[Results] The mixed application (T₃) had a more significant effect on increasing soil enzyme activity and microbial biomass carbon and nitrogen. Urease, sucrase, and dehydrogenase activities were 10.1, 9.0, and 4.5 times greater than the control, respectively. The soil microbial biomass carbon and nitrogen increased by 24.8% and 78.1%, respectively, compared to the control. In addition, mixed application could significantly improve the soil physical and chemical properties:soil salinity decreased by 62.7% and nutrient indicators increased by 57.2% to 101.4%. Inorganic amendments had less effect on soil enzymes and soil microbial biomass compared to organic amendments. The available potassium and available nitrogen were the main factors affecting soil enzymes and microbial biomass, whereas salt content and bulk density were negatively correlated with soil enzymes and microbial biomass.[Conclusion] The addition of garden waste compost played a decisive role in increasing soil enzyme activity and microbial biomass. The best application treatment group was 68 kg/m³ of garden waste compost with 15 kg/m³ of bentonite.