Wool scouring wastewater (WSW) contains diverse pollutants which are required to be effectively removed before discharge. In this work, a green and environment-friendly coagulation-flocculation-decantation (CFD) process was reported to treat WSW using synthesized polyaluminium ferric silicate (PAFS) as dominant and chitosan as adjuvant coagulants. The coagulation behavior of PAFS system, chitosan system and PAFS + chitosan system in terms of turbidity and chemical oxygen demand (COD) of the WSW was investigated with respective to the coagulant composition, dosage and pH. The results showed that PAFS performed well at large dosage and chitosan exhibited limited coagulation property. The combination of PAFS and chitosan can not only reduce the coagulant dosage by 40% for PAFS and 80% for chitosan, but also broaden the pH range, at no expense of excellent coagulation performance. The coagulation mechanism was also investigated by measuring the zeta potentials in PAFS + chitosan system, showing the synergistic effect. Overall, The combination of PAFS and chitosan was of great significance for improving WSW treatment efficiency and reducing environmental pollution.