Air purifier for farm

The invention discloses an air purifier for a farm, which comprises an inner housing, an outer housing, an air purification device arranged in the inner housing, a rack between the inner housing and the outer housing, a transmission device, an annular filter screen, a cleaning device and a drying device, wherein the inner housing and the outer housing are arranged together in a covering manner; the transmission device is coated with the annular filter screen; the transmission device can drive the annular filter screen to rotate, so as to clean a smudgy part of the annular filter screen; and the annular filter screen is dried by the drying device. When the air purifier operates normally, the filter screen can be cleaned and dried automatically, so that the manpower is saved, and the purification efficiency is guaranteed, and the filter screen is in an annular structure, so that different parts of an annular surface of the filter screen can be used piecewise and sequentially, and the service life of the filter