Abstract: The traditional tannery wastewater treatment methods appeared many problems,such as low NH₃-N removal rate, complex process, unstable processing, which are difficult to meet emission standards. In this paper, using a self-made activated bacterial solution, engineering test was carried out to optimize the traditional treatment process of leather sewage. The results showed that the optimized leather sewage treatment process displayed the characteristics with high digestibility under high mud and high oxygen conditions. The amount of sludge produced per cubic meter of sewage was greatly reduced, reaching ≤0.6 kg/m³; and NH₃-N and COD were significantly reduced, reaching ≤6 mg/L and ≤200 mg/L, respectively.This provides a reference for the sewage treatment methods of tanneries.