Currently,the global incidence rate of ulcerative colitis(UC)is increasing year by year.Conventional therapies cannot ef-fectively repair damaged tissue and reconstruct immune homeostasis,with a clinical remission rate of<50%,and most of the patients are facing problems such as drug resistance,irreversible damage to the mucosal barrier,and fibrosis,which require novel therapeutic methods.Recent studies have shown that bone marrow mesenchymal stem cells(BMSCs),with the help of their characteristics of multi-potential differentiation and inflammatory chemotaxis,can precisely modulate the microenvironment by secreting anti-inflammatory mediators and immunomodulatory proteins and significantly promote the regeneration and functional recovery of colonic mucosa.Based on these findings,BMSCs have become an important research direction in the field of UC treatment.Therefore,this article integrates ex-isting therapeutic systems and systematically analyzes the therapeutic mechanism of BMSCs,in order to provide a new theoretical basis and clinical guidance for the treatment of UC.