Method for circularly purifying water body of urban riverway ashore

The invention relates to a method for purifying the polluted water body of an urban riverway, in particular to a method for circularly purifying the polluted water body of an urban riverway ashore. The polluted water body of the urban riverway is circulated ashore by a water pump, and the sewage of the riverway is purified by units in a plant-growing filtering tank arranged on the river bank, such as a plant root layer and a substrate-adsorbing filtering layer, and then follows back into the riverway. The invention realizes plant root layer-absorbing purification and substrate filtering layer-adsorbing purification for removing the pollutants of the water body, effectively combines plant remediation and physical remediation techniques together, and is integrated with the landscape of the greenbelt of the river bank, meanwhile, the invention solves the problem on how to supply water for the daily maintenance of the plant of the greenbelt, and can be combined with the cement bank protection work, and the technique is simple and effective.