An anaerobic fermentation processing device for anaerobic microbial processing agent based organic fertilizer comprises a fermentation tank, a heat assembly and an electric circulating pump. The device is characterized in that the fermentation tank comprises a tank body, a material inlet and outlet pipe, pile foundations, a movable cover and a ring beam, wherein the ring beam is fixed at upper ends of the pile foundations; the tank body is vertically fixed on the upper end surface of the ring beam, the material inlet and outlet pipe is arranged on the outer wall of the lower end of the tank body, and a valve is arranged on the material inlet and outlet pipe; the heating assembly comprises a plurality of heating pipes, a return pipe and a hot water pipe, the plurality of heating pipes are arranged in the tank body, a water inlet of each heating pipe is connected with a water outlet of the hot water pipe, and a water inlet of the hot water pipe is connected with a heating port of an external hot water boiler; a water outlet of each heating pipe is connected with a water inlet of the corresponding return pipe, and a water outlet of each return pipe is connected with a water return port of the external hot water boiler; a water inlet and a water outlet of the electric circulating pump are connected with the interior of the tank body through pipes respectively. The device has the advantages of low manufacturing cost, high processing capacity, good processing quality, high processing speed and high production efficiency.