A fiber carding and outputting device for an air laid machine comprises a machine frame, a cotton pressing plate supported by a left wallboard and a right wallboard, an air bellow fixed between the left wallboard and the right wallboard, a cotton carding roller supported between the left wallboard and the right wallboard, a cotton supporting plate arranged under the cotton pressing plate correspondingly, and a roller mechanism supported between the left wallboard and the right wallboard and connected with a roller driving mechanism. The device is characterized in that an air outlet channel of the air bellow extends to a cotton outlet of the cotton carding roller and is connected with the front side of a guide plate on the cotton carding roller, and an airflow uniformizing plate is arranged at the position of an air outlet of the air outlet channel of the air bellow; the roller device comprises a large upper roller, a large lower roller, a small upper roller, a small lower roller and a pair of roller shaft adjusting bases, and the roller driving mechanism comprises a driving motor fixing base, a driving motor, a driving motor chain wheel, a large upper roller shaft chain wheel, a large lower roller shaft chain wheel, a small upper roller shaft chain wheel, a small lower roller shaft chain wheel, a transition tensioning chain wheel, a tensioning chain wheel and a driving chain. By the adoption of the device, it is ensured that the thickness of a non-woven cellucotton web layer is uniform, work strength is reduced, and safety is guaranteed.