Nickel mining activities often cause severe soil degradation, reducing fertility and microbial activity and hindering ecological recovery. This study evaluated the effectiveness of eco-enzyme application in improving the physicochemical and biological properties of nickel mining-contaminated soils. A laboratory incubation experiment was conducted using two soil types treated with eco-enzyme concentrations ranging from 0 to 10% and incubated for up to 30 days. Soil pH, soil organic carbon, total nitrogen, available phosphorus, cation exchange capacity, base saturation, aggregate stability, and microbial populations were analysed. The results showed that eco-enzyme significantly improved soil quality, with the best performance achieved at 10% concentration after 30 days of incubation. Under this treatment, soil pH, nutrient availability, cation exchange capacity, aggregate stability, and microbial populations increased substantially in both soil types. These findings indicate that eco-enzyme is a low-cost and environmentally friendly amendment with strong potential for sustainable rehabilitation of nickel mining-degraded soils.