Ｏｂｊｅｃｔｉｖｅ　To investigate the effect of heterogeneous ribonucleoprotein A2/B1 (hnRNP A2/B1) on the human umbilical vein endothelial cells (HUVECs) permeability induced by lipopolysaccharide(LPS).　Methods　HUVECs were used in this study, small interfering RNA (siRNA) with hnRNP A2/B1 gene silencing was screened. The samples were divided into four groups: NC siRNA group, hnRNP A2/B1 siRNA group, NC siRNA-LPS group and hnRNP A2/B1 siRNA-LPS group. The transendothelial electrical resistance (TEER) of HUVECs was detected at 0, 6, 12 h and 24 h. The expression of vascular endothelial cadherin (VE-cadherin) and intercellular adhesion molecule-1 (ICAM-1) were measured at 12 h.　Results　After LPS treatment, the TEER values of HUVECs in hnRNP A2/B1 siRNA-LPS group was significantly decreased compared with values of NC siRNA-LPS group at 12 h (P<0.05). The expression level of VE-cadherin in hnRNP A2/B1 siRNA-LPS group was lower than the level in the NC siRNA-LPS group, and the expression level of ICAM-1 was increased in hnRNP A2/B1 siRNA-LPS group compared with the level of NC siRNA-LPS group(P<0.05).　Conclusions　hnRNP A2/B1 may play an important role in vascular endothelial permeability via regulating the expression of VE-cadherin and ICAM-1, thus protecting vascular endothelial barrier function.