The invention discloses a compound constructed wetland tail water treatment system, which belongs to the field of sewage treatment technology. The system mainly includes a pretreatment and a constructed wetland system. The pretreatment portion comprises an aeration oxidation pool and an ecological gravel bed; The constructed wetland system fuses a design of stabilization lagoon, which combines a vertical current constructed wetland and a surface flow constructed wetland, and a stabilization lagoon is arranged in step in series; the tail water to be treated passes the aeration oxidation pool, the ecological gravel bed, the vertical current constructed wetland, the stabilization lagoon in order, and finally passes the surface flow constructed wetland and flows out. The system combines physical, chemical and biological means organically, thereby effectively improving the tail water quality, and the water quality of water outlet basically reaches the surface water environment standard III grade, and the water outlet can directly returns to river ecological environment for supplementing water and can be used as city miscellaneous water; the invention has the advantages of low investment, simple operation, low energy consumption, high environment benefit and ecological benefit, etc.