A treatment system for domestic wastewater, relating to the technical field of wastewater treatment. The treatment system comprises a primary treatment system, a secondary treatment system, and a sludge treatment system; the secondary treatment system comprises a biochemical tank (21) and a sedimentation tank (22) that are sequentially connected; the biochemical tank (21) is connected to the primary treatment system; the secondary treatment system further comprises a second cylcone separator (23) and a power pump (24); one end of the power pump (24) is connected to a sludge outlet of the sedimentation tank (22) by means of a pipeline, and the other end of the power pump (24) is connected to a second feed pipe (232) of the second cylcone separator (23); a second underflow port (233) is connected to the biochemical tank (21) by means of the pipeline; a second overflow port (234) is connected to the sludge treatment system by means of the pipeline. After active sludge is treated by the second cylcone separator (23), the activity of the active sludge is increased by at least 15%, thereby improving the utilization rate of a resource, reducing the cost of an overall treatment system, also improving degradation efficiency in the biochemical tank, and facilitating popularization.