Abstract: This study investigates the pretreatment effects of two chemical flocculants, polyacrylamide (C-PAM) and polyaluminium chloride (PAC), on actual pig wastewater under single and composite (C-PAM + PAC) addition conditions. The optimal composite ratio and the effects of C-PAM and PAC dosages on the removal of ammonia nitrogen, turbidity, total phosphorus, and COD from the wastewater were determined. When C-PAM was added alone at an optimal concentration of 0.2% and a dosage of 14 mg, the best removal rates for ammonia nitrogen, turbidity, total phosphorus, and COD were 56%, 86%, 85%, and 71%, respectively. Conversely, the optimal dosage of PAC alone was 500 mg, achieving removal rates of 52% for ammonia nitrogen, 88% for turbidity, 95% for total phosphorus, and 76% for COD. When using a composite of 0.1% C-PAM and 10% PAC at an optimal dosage of 5 mg C-PAM + 750 mg PAC, the optimal removal rates of pollutants were 63% for ammonia nitrogen, 99% for turbidity, 99% for total phosphorus, and 73% for COD. The experimental results indicate that the composite flocculants exhibit significantly superior treatment performance compared to single flocculants. Therefore, this study provides a valuable reference for the pretreatment of pig wastewater.