The invention discloses a small-scale decentralized integrated device for ecological purification of domestic sewage at a suspended sewage outlet of a river, which includes a sewage collector at the sewage outlet, an upflow sedimentation sand filter, a three-stage ecological purification cage and a solar aeration system; the three sections The ecological purification cage is composed of an anaerobic treatment bag, a solar-driven contact oxidation bag and a deep adsorption decontamination water outlet end-to-end; the device collects the waste water from the sewage outlet through the waste water collector, and enters the third section after flowing through the upflow sedimentation sand filter Type ecological purification cage, the three-stage ecological purification cage is composed of waterproof cylinder and plastic flange, and finally discharged into the river through the outlet; at the same time, the three-stage ecological purification cage is fixed on the inner side of the river bank by anchor rods, and the device The resulting exfoliated biofilm can be manually removed. The device has novel and simple structure, convenient maintenance, no additional energy consumption, good river landscape effect, and does not affect flood control safety, and has strong application and promotion value.