Abstract When the polymer concentration in the produced fluid increases, the viscosity of the sewage will increase, the overall flow velocity of the fluid in the cyclone will decrease, the kinetic energy will decrease, the wall friction resistance will increase, and the tangential velocity will decrease overall. The performance of the cyclone is degraded. The structure and parameters need to be adjusted and optimized. By optimizing the design of the structure and parameters of the inlet fluid channel, the oil-receiving port, etc., a new type of oil-water cyclone is designed. Numerical experiments show that the new type of oil-water cyclone is effective for the separation of low oil content of polymer-containing sewage. Through indoor experiments and on-site pilot scale-up, 5# cyclone was modified with a new type of oil-water cyclone in the West II Joint Processing Station. The field test and production daily report data show that the improved 5# cyclone is effective. The polymer-containing sewage treatment can obtain stable results. The oil content of the effluent is better than the original cyclone indicator. When the oil content of the polymer-containing sewage at the inlet is 100-300mg/l, the average oil content of the outlet is less than 100mg/l, Meets the design requirements, indicating that the improved cyclone structure and parameters are suitable for the treatment of polymer-containing sewage, and the newly designed cyclone is effective for the treatment of polymer-containing wastewater.