n order to improve the removal efficiency of turbidity, organic matter (CODMn), and ammonia nitrogen in the low temperature and low turbidity water of the Yellow River in Lanzhou by the coagulation method, the Box-Behnken's center combination design method was used to study the effects of PFAC coagulant dosage, PAM coagulant dosage, flocculation speed and flocculation time and their interactions on turbidity removal, permanganate index removal, and ammonia nitrogen removal. The results show that the best removal conditions of turbidity, organic matter and ammonia nitrogen are as follows: PFAC Coagulant dosage 7.87 mL, PAM coagulant dosage 6.06 mL, flocculation time 37 min, flocculation speed 90 r/min, respectively. Under the optimal conditions, the removal efficiencies of turbidity , CODMn and ammonia nitrogen were 16.3%, 19.7%, and 14.7% , respectively. The turbidity is 0.76 NTU, the permanganate index is 2.72 mg/L, and the ammoniacal nitrogen is 0.44 mg/L after the coagulated effluent was filtered through sand. which suggest that the effluent can meet the “Standards for Drinking Water Quality” (GB 5749-2006). The research results provide technical support for the upgrade and reconstruction of the treatment process of Lanzhou City Water Supply (Group) Co., Ltd.