The invention relates to a sewage treatment system for an artificial wetland primarily, which comprises a bar screen, a water-collecting tank, a flocculation drug mixing tank, a sedimentation tank, an aeration tank and the artificial wetland connected in turn, wherein the base material of the artificial wetland comprises one or more of sand soil mixture, crushed stone, zeolite, limestone, coal slag, steel slag, blast furnace slag, crushed stone, porcelain granules, melon seed piece and pebble; the water outlet of the sedimentation tank is provided with an overflow weir for yielding water; and a stirring paddle is arranged in the flocculation drug mixing tank. The sewage treatment system greatly reduces the concentration of pollutants entering the sewage in the artificial wetland, and certain pollutants difficult to perform biochemical treatment can also be taken out in a mode of flocculation sedimentation, thus the content of the pollutants entering the sewage in the artificial wetland is reduced so as to reduce the area of the artificial wetland, reduce the sedimentation of the pollutants in the artificial wetland, and avoid the generation of the problems of blockage and the like. The sewage treatment system is mainly adapted to domestic sewage and other similar organic sewage.