Types of wastewater from a pulp and paper mill is pulping wastewater which is discharge water for the process. The capacity is 45,000 m3/d. Due to the unstable production process, it makes the biological system is impacted by the inlet water quality fluctuates greatly. To improve the resistance impact of biological systems and stabilized effluent COD and S.S. After Bioaugmentation and long keeping dosing, the impact resistance of biological system has improved. The sludge settlement in the latter stage increases, the COD of the effluent is stable below 120 mg/L (standard < mg/L), and the S.S. is lower than 10 mg/L (standard < mg/L).