Abstract: The consultation index and limitation of produced water quality is provided to oilfield by researching on the influence of Na+，K+，Ca2+，Mg2+，Fe2+，Fe3+ cations and the initial viscosity.And the factor analysis of the influence of polymer solution stability is carried out including dissolution oxygen，cation，clay mineral and bacterium.The cation content is major factor influencing initial viscosity，the order being Fe2+＞Fe3+＞Mg2+＞Ca2+＞Na+＞K+.When polymer solution is prepared，the basic requirement of produced water is none Fe2+ and Fe3+，and Ca2+ content is under 200mg/L with the optimal value of 50mg/L，Mg2+ content under 100mg/L with the optimal value of 30mg/L，Na+，K+ content under 2000mg/L with the optimal value of 500 mg/L.Dissolution oxygen and high valence cations are major factors influencing polymer solution stability，the order being Fe2+>Mg2+（Ca2+）>Fe3+>Na+（K+）.One band valence bond cation and suspension influence polymer solution stability to a certain degree.The influence of bacterium is relative small.Oxidation-reduction reaction is maximum influence on polymer solution stability.

Key words: cation content, produced water, influence factor, polymer solution, stability, dissolution oxygen