The invention relates to a reoxygenation device based on a windmill for constructed wetland. The reoxygenation device comprises a reoxygenation pipe and the windmill, wherein the reoxygenation pipe isof a tubular structure with openings at two ends; one end of the reoxygenation pipe is inserted into a wetland substrate; one end of the reoxygenation pipe is connected with the windmill and is usedfor receiving and accelerating the airflow; the reoxygenation pipe can also be formed by a plurality of reoxygenation pipes with openings at two ends and with different pipe diameters and lengths through coaxial sleeving and lamination or parallel arrangement; the reoxygenation pipe is connected with the windmill for jointly forming the reoxygenation device provided by the invention. The inventionalso provides a method for the constructed wetland reoxygenation by using the reoxygenation device. The reoxygenation device provided by the invention has the advantages that the structure is simple;the material achieves the environment-friendly effects; the cost is low; the method for constructed wetland reoxygenation by using the reoxygenation device is simple; the implementation is easy; theenergy is saved; the environment is protected; the maintenance cost is low; the reoxygenation effect is good; the operation efficiency is high; the application range is wide.