LOC anaerobic reactor is developed on the basis of traditional UASB reactor and EGSB anaerobic reactor. The core of LOC anaerobic reactor is based on a specially designed water distribution and three-phase separation module, which realizes the highly turbulent state of wastewater in the reactor, promotes the full contact between wastewater and anaerobic microorganisms, improves the efficiency of anaerobic mass transfer reaction, and effectively intercepts biological carriers to ensure that the reactor is always in the interior. In a state of high efficiency and benign circulation, the pollutants in water are degraded by a large margin, and the by-product biogas can be used as energy.