Municipal drainage system and construction method

The invention relates to the technical field of municipal drainage treatment and discloses a municipal drainage system which comprises a greening permeating lawn which is used for collecting rainwater. A road surface permeating system comprises a greening lawn arranged between a motor vehicle lane and a non-motor vehicle lane, small down-flow holes formed in the edge of the motor vehicle lane and down-flow ports formed in a manway zebra crossing. A rainwater collecting pipe collects the rainwater permeating from a road surface permeating net and entering the rainwater collecting pipe, a settling pond is used for depositing the rainwater and collecting the rainwater with particle impurities, the rainwater after sedimentation enters a domestic sewage purification processor, and after being purified though the domestic sewage purification processor, the rainwater flows into a purified water collecting tank. The municipal drainage system is simple in structure and convenient to lay; through the matching of a rainwater collecting tank, the settling pond and the purified water collecting tank for use, generated sewage can be buffered to some extent, and the problem that the flow is too large, so that the drainage system breaks down and people's normal life is affected is solved.