Static water body self-purification system

The invention provides a static water body self-purification system which comprises a pool body, a grating plate, a porous medium layer, a subsurface wetland and a sewage lifting mechanism. The grating plate is horizontally arranged in the pool body, and a sedimentation space is reserved between the grating plate and the bottom of the pool body. The porous medium layer is laid on the grating plate. The subsurface wetland surrounds the pool body, the bottom of the subsurface wetland is higher than the grating plate, and a reflux inlet communicated with the pool body is formed in the bottom of the subsurface wetland. The lifting mechanism comprises a pool bottom water pumping pipe network, a submersible pump and a lifting pipe, wherein the pool bottom water pumping pipe network is laid at the bottom of the pool body, the submersible pump is arranged at the bottom of the pool body, the input end of the submersible pump is connected with a water outlet of the pool bottom water pumping pipe network, the output end