Abstract: The composite technology formed by the combination of single technologies has been widely used in the treatment of black and odorous rivers. A composite microbial technology combining membrane aerated biofilm reactor (MABR) and microbial inoculant was proposed and applied to the actual treatment on a small black odorous river. The results showed that after 61 days of commissioning, the transparency, ORP and DO concentration increased, the ammonia nitrogen concentrations and COD decreased, although the water quality repeated ups and downs during the commissioning operation. The Transparency and ORP dropped while ammonia nitrogen concentrations and COD rebounded during rains, and water quality returned to normal after 7 days, which meant that the composite technology had a certain impact resistance capacity. After 6 weeks of stable operation, the transparency, ORP and DO concentration of the river increased by 157%, 57% and 308%, respectively, and ammonia nitrogen concentrations and COD decreased by 65.0% and 71.4%, respectively, thus eliminating the black and odor of the river. This composite microbial technology presented a good effect on the engineering of eliminating the black and odor and the system could last for a long time, but the ability to improve the water quality was limited. To improve the river water quality to surface water environmental quality standards, the systematic, ecological and intelligent comprehensive control measures should be further promoted.