The invention discloses a microorganism denitrification treatment device. The microorganism denitrification treatment device comprises a box body, a plurality of microorganism carriers, an electromagnetic flowmeter, a dissolved oxygen determination module, an aeration device and a controller, and a plurality of upper frames, a plurality of lower frames, a water guide pipe and a water outlet are arranged in the box body. The upper frames positioned on the same horizontal plane are transversely arranged and close to the upper port of the box body, two ends of each of upper frames are fixedly connected with the left surface and the right surface of the box body respectively, the lower frames which are positioned on the same horizontal plane are transversely arranged and close to the bottom ofthe box body, and two ends of each of the lower frames are fixedly connected with the left surface and the right surface of the box body respectively. Each microorganism carrier comprises an upper fixing rod, a lower fixing rod and a plurality of porous wires, and the upper fixing rod and the lower fixing rod, which are arranged transversely, of each microorganism carrier are horizontally arranged and are positioned on the same vertical plane. By the aeration device in the invention, accurate aeration can be realized, intelligent degree is high, and energy saving and consumption reduction areachieved.