Smoke exhaust pipe for building

The utility model relates to the field of building smoke exhaust, in particular to a smoke exhaust pipe for a building. A filter screen plate is fixedly connected to the inner wall of the smoke pipe, a scraping and cleaning assembly used for cleaning the surface of the filter screen plate is arranged on one side of the filter screen plate, and a spraying assembly used for spraying cleaning liquid to the surface of the filter screen plate is arranged on one side of the filter screen plate; smoke with greasy dirt discharged from the smoke pipe can be filtered through the filter screen plate, the greasy dirt and harmful substances in the smoke discharged from the smoke pipe can be reduced, the spraying assembly can spray greasy dirt cleaning agents to dissolve the greasy dirt on the surface of the filter screen plate, and at the moment, dirt on the surface of the filter screen plate can be scraped and brushed through the scraping and cleaning assembly. The oil dirt falls into the collecting assembly, and the oil