Abstract: In view of the difficulties in long-term maintenance of the treatment effect of black odorous river and the problem of black and odorous repeatedly, an in-situ ecological restoration was carried out in a seriously polluted black odorous river course with severe internal pollution. In the first stage, ultrafine bubble oxygen enrichment (mobile aerator+fixed point aerator) and biological activation technology were used to restore water and sediment, reduce endogenesis pollution and improve living environment; in the second stage, the fixed point aerator, ecological floating island, purification of aquatic plants and diversity regulation of aquatic animals were applied, to restore and create a healthy and stable ecosystem. After nearly 4 months’ treatment, the water quality in the treated area stabilized from severe black odor to the surface V water standard, and the contents of COD, NH₃-N and TP were 28.79, 0.36 and 0.19 mg/L, and the removal rates reached 45%, 98% and 85% respectively. After the treatment, the water was clarified and a variety of aquatic animals and submerged plants were visible. The channel sediment had a natural earthy color. The mud-water co-treatment effect was achieved without dredging treatment. The quality of the water environment was significantly improved and long-term governance aim was achieved.