The wastewater from this coal chemical enterprise is complex in composition, containing oil, phenol, ammonia nitrogen, and suspended solids, and the original process treatment effect is not ideal. We have customized a composite flocculation scheme of polyferric sulfate (PFS) and cationic polyacrylamide (PAM) for it. After combined treatment with air flotation and flocculation precipitation, the suspended solids removal rate reaches over 95%, the COD removal rate is increased by 30%, and the effluent meets the requirements for subsequent biochemical inflow. The system operates stably.