River biological filter bed

The utility model discloses a riverway biological filter bed. The method is applied to the biofilter field. The technical problem that river water bottom purification is not thorough is solved. According to the key points of the technical scheme, the device comprises a filter material layer laid at the river bottom and a plant layer located at the upper end of the filter material layer, the filter material layer comprises a microbial filter material for denitrification reaction and a limestone pyrite filter material for dephosphorization reaction; a floating island is arranged at the lower end of the plant layer; a plurality of screen frames are arranged at the river bottom; the microbial filter material and the limestone pyrite filter material are filled in the screen frame; a plurality of retaining walls are arranged in the riverway in the length direction of the riverway, cross beams are arranged at the upper ends of the retaining walls in the direction perpendicular to the retaining walls, and the floatin