The invention discloses an oil extraction wastewater treatment method used for oilfield reinjection, comprising the following steps of: desulphurization and deferrization, adjustment of pH value, cohesion degreasing and suspension particles removing, and flocculating setting. The oil extraction wastewater treatment method provided by the invention overcomes the shortcomings that inorganic flocculants, organic flocculants, fungicides, HAG (antiincrustation corrosion inhibitor) and other drug agents are needed to be added and the treatment cost is high during oil extraction wastewater treatment in the past, has the advantages of simple treatment method, simple operation, low treatment cost, and high treatment efficiency, and solves the problem of stable water quality during wastewater reinjection treatment course.