An air cleaning system for a vehicle includes: an air purification button generating an operation signal for purifying air in an interior of the vehicle; an inside air purification unit blocking air outside of the vehicle from being introduced into the interior of the vehicle and filtering and circulating air inside of the vehicle, when the air purification button is operated; a fog detection unit detecting a humidity of a window of the vehicle by detecting moisture on the window; and a controller controlling an operation of the inside air purification unit when the air purification button is operated and determining whether a defogging unit of the vehicle for removing the moisture on the window is to be operated based on a signal from the fog detection unit.