Ecological system for improving self purification capacity of riverway and construction method of ecological system

The invention relates to the technical field of self purification of riverways, in particular to an ecological system for improving the self purification capacity of a riverway and a construction method of the ecological system. The system comprises the riverway, side slopes arranged on the two sides of the riverway and infiltration dams arranged on the riverway at intervals, wherein a stone purification layer is arranged on the surface layer of the river bottom of the riverway. A soil layer is further arranged on the stone purification layer. Water is arranged on the soil layer. An aquatic plant community layer is arranged on the surface layer of the water. Ecological bags are arranged on the side slopes. A vegetation layer is arranged on the surface of each ecological bag. The complete riverway ecological system is constructed in a staging manner through a chemical method, a biological method and an ecological method according to different water quality conditions; the water qualityis purified, and meanwhil