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 .