A　computational　fluid　dynamics　(CFD)-based　method　combined　with　water　chemistry　and　electrochemical　reaction　calculation　is　developed　to　investigate　the　effect　of　fluid　flow　on　carbon　dioxide　corrosion　in　an　elbow.　The　mass　transfer　of　reactants　and　products　influenced　by　flow　during　corrosion　is　revealed　visually　by　distribution　of　main　species　concentration.　The　results　show　that　the　distributions　of　main　species　concentration　and　corrosion　rate　on　the　bare　steel　surface　are　in　good　accordance　with　the　distribution　of　flow　velocity.　The　maximum　corrosion　rate　appears　at　the　entrance　on　inner　side　wall　of　the　elbow,　and　the　corrosion　rate　decreases　along　the　flow　direction.　Near　the　exit　of　the　elbow,　the　secondary　flow　arises　and　enhances　the　mass　transfer　as　well　as　the　corrosion　rate.　According　to　the　saturation　value,　the　iron　carbonate　is　more　likely　to　precipitate　at　the　inner　side　wall　near　the　exit　of　the　elbow.　The　model　is　validated　by　the　good　agreement　between　simulation　results　and　published　experimental　data　in　prediction　of　hazardous　corrosion　region　and　the　regional　corrosion　rate　of　the　elbow.