Belonging to the field of sewage denitrification treatment, the invention discloses a membrane aerated biofilm micro-aerobic sludge bed process and a wastewater treatment method thereof. The membraneaerated biofilm micro-aerobic sludge bed process adopts a biofilm micro-aerobic sludge bed, a sludge bed water inlet pipe, a sludge bed water outlet pipe, a sludge discharge pipe, a biofilm aeration component, an air pump, a circulating pump, a peristaltic pump, air flow meters and pressure gauges. The treatment method realizes the mutualism and collaborative metabolism of aerobic bacteria, anaerobic bacteria and facultative anaerobes in a micro-aerobic environment, at the same time utilizes the efficient oxygen mass transfer efficiency of the membrane aeration component and enables wastewaterto flow on the outer surface of the biofilm to form back diffusion of oxygen and pollutants, and can realize effective removal of pollutants in a bioreactor. The process and the treatment method provided by the invention are suitable for denitrification treatment of urban sewage and industrial wastewater, and have the advantages of high treatment efficiency, high energy utilization rate, stable effluent effect, fast start-up speed, etc.