In order to clarify the influencing factors of oil-water interfacial film stability of polymer flooding produced liquid in Bohai S oilfield，the influence of polymer type，mass concentration of hydrophobic associating polymer and salinity of aqueous phase on thestability of crude oil emulsion was evaluated by the characterizations of oil-water interfacial rheology，Zeta potential and interfacial tension. The results showed that compared with linear polymer，hydrophobic associating polymer had obvious thickening and viscosifying effect on crude oil emulsion in BoHai S oilfield，which could significantly change the oil-water interface electrical property，increase the oil-water interface activity，enhance the strength of oil-water interface membrane，and had better emulsion stability. At the same time，there was a linear correlation between the concentration of hydrophobic associating polymer and the interfacial membrane elasticity of the emulsion. With the increase of the polymer concentration from 0 mg/L to 800 mg/L，the interfacial membrane elasticity of the emulsion increased from 4 Pa to 17 Pa. When the mass concentration of polymer increased up to 400 mg/L，the adsorption of the polymer at the oil-water interface was close to saturation. The water phase salinity also had a great influence on the stability of crude oil emulsion. When the salinity was 0—9417.7 mg/L，the stability of the emulsion was mainly affected by the electrical properties of the interface；while when the salinity of aqueous phase was 9417.7 — 18，835.4 mg/L，the stability of emulsion was mainly affected by the structural strength of oil-water interface membrane.