Objective To review the basic research, the cl inical progress, and the mechanism of bone marrow mesenchymal stem cells (BMSCs) in acute lung injury (ALI). Methods The l iterature concerning the basic and cl inical researches of BMSCs in ALI was reviewed. Results BMSCs can take the initiative to “homing” the site of lung injury and take partici pate in repair by means of differentiation, meanwhile BMSCs could regulate and balance local and systematic inflammatory response and immune disorders in ALI. Currently, the mechanism of BMSCs on anti-inflammation and immune regulation in ALI is not clear. Conclusion BMSCs have comprehensive biological effect on ALI, providing a potential cl inical treatment and also laying the foundation for gene therapy and stem cell therapy of ALI in the future.