The structure, distribution and functions of root channels in the soil system were reviewed. Root channel is one important component of macropores in the soil system. It is a multimedia interface, which involved with plant root, soil, microbe, water and air. It plays an important role in soil preferential flow, solute transportation, pollutant absorption and transform. In natural and constructed wetlands, the developed root channel system in the soil constructed a pollutant transport channel, absorption in...