Aquifer water with high iron and high CO2 content is used as the source of injection water for an oilfield in Iraq. As similar water quality treatment experience is rare in projects both at home and abroad, it is necessary to develop a practical and economical process system for water treatment. Via the investigation for degassing treatment facilities and iron removal facilities; after process comparison and simulation experiments, an economically viable and technically robust water treatment technology was proposed. Through simulation experiments, it is demonstrated that the treatment process can reach the following treatment performance indicators: Total iron content was reduced from 71 mg/L to 0.5 mg/L, CO2 from 225 mg/L to 10 mg/L, TSS from 98 mg/L to 10 mg/L, and dissolved oxygen from 1 mg/L to 0.05 mg/L, meeting the specifications of the injection water of the oil field. The research results provide reference for the treatment process flow selection of aquifer water with high iron and high CO2.