Municipal sewage filtration and purification system

The utility model relates to a municipal sewage filtration and purification system. The municipal sewage filtration and purification system comprises a rough filtration tank, a desilting basin and a refined filtration tank, wherein the rough filtration tank is mutually communicated with the desilting basin by virtue of a water permeable opening; the refined filtration tank is mutually communicated with the desilting basin by virtue of a connecting pipe; the rough filtration tank comprises a rough filtration bin arranged at an upper layer and a deposition bin arranged at a lower layer; filter cotton is arranged on the rough filtration bin arranged at the upper layer, and a sewage inlet is formed in the upper side of the rough filtration bin; the filter cotton is arranged on the bottom of a pool at the upper layer; a plurality of water permeable holes are formed in the bottom of the pool at the upper layer; the deposition bin at the lower layer comprises a sewage outlet formed in the side at the lower layer and