Aim To investigate the effect of low shear stress (LSS) on the expression of Bmi-1 in human umbilical vein endothelial cells (HUVEC) and its possible mechanism. Methods Human umbilical vein endothelial cells were cultured in vitro. Immunofluorescence was used to detect the localization of Bmi-1 in the cells. 0.5 h, 1 h, 2 h and 4 h were loaded into human umbilical vein endothelial cells by parallel plate flow chamber system. The expression of Bmi-1 mRNA was detected by real-time quantitative RT-PCR. The expression of Bmi-1 protein was detected by Western blot.Specific signal inhibitor SB2219 was used to investigate the signal transduction pathway. Results Immunofluorescence observation showed that Bmi-1 was mainly distributed in the nucleus of human umbilical vein endothelial cells. The expression of Bmi-1 was significantly increased after 0.5 h of LSS, the expression of Bmi-1 mRNA and protein decreased gradually with the prolongation of the time (1 h, 2 h and 4 h); the shear stress could significantly activate phosphorylated p38 expression; SB2219 could significantly inhibit the expression of Bmi-1. Conclusion LSS can induce the expression of Bmi-1 in human umbilical vein endothelial cells, the expression of Bmi-1 is closely related to the length of stimulation, this effect may be regulated by p38 signal.