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.