The invention discloses a biological drainage treatment device which comprises a vegetation reaction tank and a return pipe, wherein the upper end of the vegetation reaction tank is provided with a water inlet pipe; floating plants are arranged in the vegetation reaction tank; a water outlet of the vegetation reaction tank is communicated with a water inlet of a microbe reaction tank through a guide pipe; microbes are arranged in the microbe reaction tank; a water outlet of the microbe reaction tank is communicated with a water inlet of an adsorptive sterilization tank through a guide pipe; a plurality of filter screens are arranged in the adsorptive sterilization tank; the surface of the water inlet pipe, the surface of the drainage pipe, the guide pipe between the vegetation reaction tank and microbe reaction tank, the guide pipe between the microbe reaction tank and adsorptive sterilization tank, the guide pipe between the adsorptive sterilization tank and drainage detection tank and the joint between the return pipe and return port are respectively provided with a solenoid valve; the outer side of the drainage detection tank is provided with a controller; and the controller is electrically connected with a water quality detection instrument and the solenoid valves.