The invention discloses a domestic sewage treatment device and a treatment method thereof, and belongs to the technical field of sewage treatment. The device comprises an aerated grit chamber, an anaerobic tank, an anoxic tank, an aerobic tank, a secondary sedimentation tank and a reaction sedimentation tank which are connected in sequence, wherein the secondary sedimentation tank is provided with a sludge reflux pipe connected with the anaerobic tank and the anoxic tank, the sludge reflux pipe comprises a branch pipe connected with the anaerobic tank and a branch pipe connected with the anoxic tank, the first branch pipe is provided with a first electromagnetic valve for adjusting the opening degree, the second branch pipe is provided with a second electromagnetic valve for adjusting the opening degree, the aerated grit chamber comprises a circular chamber body, a water inlet, a water outlet, more than one aeration pipe and a sand collecting tank arranged at the bottom of the circular chamber body, the aeration pipes are annularly distributed by taking the circle center of the circular chamber body as the center, the water inlet is formed in the side wall of the circular chamber body in the tangential direction, and the water outlet is formed in the side wall of the circular tank body and is perpendicular to the water inlet. The device of the invention is more thorough in desilting, various in treatment mode and convenient for outward transportation of sludge, and meets the sewage treatment requirements.