Roof drainage valve assembly

The utility model provides a roof drainage valve assembly, which belongs to the technical field of drainage and comprises a first filter cartridge, a second filter cartridge and a floating body. The first filter cylinder extends into the drainage pipe and is of a conical structure with the diameter gradually reduced downwards in the axial direction of the drainage pipe, an annular plate used for being in lap joint with a roof surface is fixed to the top of the first filter cylinder, and the annular plate is arranged around a water inlet of the drainage pipe; the second filter cartridge is arranged on the roof in the axial direction of the first filter cartridge, the bottom surface of the second filter cartridge is detachably connected with the top surface of the annular plate, and the second filter cartridge is of a conical structure with the diameter gradually reduced upwards in the axial direction of the first filter cartridge; the bottom face of the floating body is a flat plate face perpendicular to the a