The treatment and prognosis for severe acute pancreatitis (SAP) is currently unsatisfactory showing a high incidence of morbidity and mortality. Here, we investigated the effect of bone marrow-derived mesenchymal stem cells (BMSCs) on SAP in rats and explored the possible mechanisms. The common bile duct of each model rat was occluded at the liver hilum, and the induction of SAP was achieved by retrograde perfusion of 3% sodium taurocholate (NaT). Prepared BMSCs were intravenously injected via the tail vein. Pancreatic acinar cells (PACs) were isolated from rat pancreas, and induced by TNF-alpha. In the present study, we found that necroptosis was activated in NaT-induced acute-necrotized pancreatitis, and transplanted BMSCs could inhibit necroptosis, repair pancreatic injury, and reduce systemic inflammatory response. In addition, necrostatin-1 (Nec-1), as the inhibitor of receptor-interacting protein kinase 1 (RIPK1), could also reduce SAP to some extent. Besides, we detected that BMSCs could also promote regeneration of damaged pancreatic tissues. Furthermore, in vitro, we also investigated that BMSCs could suppress TNF-alpha-induced necroptosis and improve the viability of PACs. In addition, Nec-1 and knockdown of receptor-interacting protein kinase 3 (RIPK3) or mixed lineage kinase domain-like protein (MLKL) could also inhibit necrosis of PACs induced by TNF-alpha. BMSCs ameliorated SAP and reduced injury of PACs by suppressing the activation of the necroptosis signaling pathway.