Abstract: there are lots of sulfate reducing bacteria (SRB), saprophytic bacteria and iron bacteria in oil field produced water which is highly corrosive substances. So the corrosion in produced water injection well is severe. Under the conditions of meeting the existing water injection well string working parameters, the anti-corrosion flexible composite injection string was developed by changing the material and structure of water injection well string. The pipe strength check, indoor performance evaluation experimental, injection string combination design and field application study were done to test the flexible composite pipe behavior. The results showed that the flexible composite pipe can be used for more than15 years in existing water injection working conditions, which is more than three times of steel tubing life. Successfully application means a breakthrough and supplies a new method for corrosion resistance of injection well string.