The invention provides a nesting mixed flow constructed wetland, comprising an internal wetland unit, an external wetland unit, a baffle plate and wetland plants; the internal wetland unit is nested in the external wetland unit, the two wetland units are communicated by arranging a perforated plate, the internal wetland unit and the external wetland unit adopt different wetland types and are isolated by the baffle plate, one wetland unit is provided with an inflow pipe, and the other wetland unit is provided with an outflow pipe, and the internal wetland unit and the external wetland unit are both planted with wetland plants. The nesting mixed flow constructed wetland has compact layout, relative high landscape value, high decontamination efficiency, good purification effect, simple structure, convenient operation and maintenance, low investment and low operation cost, fully utilizes land types, saves occupied area, can realize zero release of sewage in city blocks, and combines the advantages of sub-surface flow wetland and surface flow wetland.