Bronchial asthma is a respiratory disease characterized by airway inflammation. Mesenchymal stem cells（MSCs）, which are expected to become a new treatment for asthma, can effectively improve airway inflammation in the animal models of asthma. Studies have shown that MSCs can achieve the goal of immune regulation by releasing transforming growth factor-β₁ （TGF-β₁） to modulate airway inflammation and airway remodeling. However, the mechanisms are unclear. This article will review the research progress of the TGF-β₁ mechanism in MSCs treatment of asthma.