Provided are a composition for use in preventing or treating lung disease comprising mesenchymal stem cells overexpressing CD47 as an active ingredient. The mesenchymal stem cells overexpressing CD47 show a high survival rate and ability to migrate to lung tissues in vivo even when they are not autologous, reduce the inflammatory response in lung tissues, and exhibit the effect of suppressing fibrosis, and therefore can be widely used for the prevention or treatment of various lung diseases associated with lung inflammation or fibrosis.