Domestic sewage treatment system

The utility model provides a domestic sewage treatment system and relates to the technical field of domestic sewage treatment. The constructed wetland comprises a medium planting bed and a marsh-like supporting bed; and the medium planting bed is arranged on the marsh-like supporting bed and is used for planting wetland plants, so that the problem that the growth space provided by the plants is insufficient due to the fact that the plants in the existing constructed wetland are mostly planted in a potting or hole digging manner is effectively solved. In addition, the marsh-like supporting bed comprises at least one perlite silt layer, at least one activated carbon silt layer and at least one perlite layer; every two adjacent layers of the perlite silt layer, the activated carbon silt layer and the perlite layer in the marsh-like supporting bed are different. According to the marsh-like supporting bed, the perlite and the activated carbon are added into the pollutant-containing material through the specific la