The invention discloses a cleaning device and a cleaning method of an elevator doorsill. An elevator comprises a landing door, a car door and an elevator control system. The cleaning device comprises: a cleaning port arranged at the bottom of the landing door and / or the car door; an air supply component, which is matched with the cleaning port and electrically connected with the elevator control system, wherein one end of the air supply component is connected with the cleaning port through a ventilation pipeline, the other end of the air supply component is connected with a storage component through the ventilation pipeline, and the air supply component is used for acquiring a control instruction of the elevator control system, generating corresponding forward or reverse wind, and conducting dust collection or dust blowing operation on the elevator doorsill through the wind; and a storage part, which comprises an exhaust outlet, wherein the exhaust outlet is formed in the side, opposite to the ventilation pipeline, of the storage part, the exhaust outlet is provided with a filter screen, and the storage part is used for containing sundries entering from the ventilation pipeline.