【Abstract】 Objective To explore the mechanism of the bone morphogenetic protein4 (BMP4) promote apoptosis of intestinal intraepithelial lymphocytes through downregulating IL7/IL7R signaling after I/R. Methods Mouse intestinal I/R model was established. The mice were randomly divided into I/R group and sham operation group. IL7 protein expression in IECs (immunofluorescence) and IL7 receptor(CD127) and phosphorylation of STAT5 proteins in IELs (flow cytometry) were detected. Westernbolt detect the change of IL7protein expression after treating the IEC6 with exogenous BMP4 protein for 6 hour. IELs were stimulated with exogenous BMP4 and BMP4 antagonist NOGGIN protein. IL7 receptor (CD127) and PSTAT5 proteins expression were measured by flow cytometry. IEL was stimulated with exogenous BMP4 and IL7 protein. The apoptosis was detected. Results The IL7 protein secretion of I/R group significantly decreased, compared with that of sham group after I/R in IECs. The IL7 receptor (CD127) and PSTAT5 expression of I/R group were also decreased after I/R in IELs(P＜005). Under condition of exogenous BMP4 stimulation, the expression of IL7 protein was decreased in IEC6, and the expression of CD127 and PSTAT5 protein also decreased in IELs(P＜005）. The apoptosis of IELs were significantly increased with BMP4 protein stimulation than the control group(P＜005）. However, IL7 protein can promote the apoptosis of IELs（P＜005）. Conclusion The IECs derived BMP4 protein downregulates IL7/IL7R signaling pathway in I/R. The protective factors of IELs are decreased, and the apoptosis rate of IELs is increased.