Aim To investigate the signaling mechanism of estrogen reducing endoplasmic reticulum stress induced apoptosis, to explore the protective mechanism of the effect on cardiovascular, through establishing the ER stress cell model in human umbilical vein endothelial cell. Methods To establish ERS cell model, HUVECs were incubated in 10 μmol/L tunicamycin (TM) or 2 mmol/L dithiothreitol(DTT) with or without 10-8 mol/L 17β-estradiol(E₂) pretreatment. Tested glucose regulated protein (GRP78) to determine whether the model was successfully established and explored the impact of E₂ in ERS. The changes of three major signaling pathway proteins of ERS were detected by Western blot, and the most significant increase is the most important signal pathway of ERS. To explore the impact of E₂ in apoptosis induced by ERS, the apoptosis protein C/EBP-homologous protein( CHOP) was analyzed by Western blot and the apoptosis rate of cells was tested by Hochest staining. To explore the role of estrogen receptor in its suppression of ERS, we added ICI182780 (ERα, ERβ antagonist and GPER agonist) and G15(GPER antagonist) before adding E₂, and analyzed the expression of the main signal pass of ERS by western blot. Added the inhibitors of E₂ receptor signaling, to explore the main post-receptor signaling pathway. Results The expression of GRP78 was significantly increased in TM/DTT group,and the protein kinase R-like ER kinase(PERK) was the most significant increase one among the three signaling pathways of ERS. In the presence of E₂, the regulations replied. The expression of CHOP and the apoptosis rate of cells were significantly increased in TM/DTT group,and regulations replied when added E₂. The inhibition of E₂ to the up-regulation of p-PERK/PERK was inhibited by ICI182780 and G15 respectively, the blocking is the most obvious while adding both. The effect of E₂ reduced p-PERK/PERK were weakened when added the inhibitors of E₂ receptor signaling respectively,and the weakness was the most obvious when added the signaling inhibitor of Akt. Among them, the effect of PI3K-Akt inhibitor was the most significant. Conclusions E₂ can protect human endothelial cells from ERS induced by TM and DTT. p-PERK/PERK pathway may be the most important signal path of ERS. E₂ plays a role in inhibiting HUVEC apoptosis induced by over ERS. The receptors of E₂ play an important role when E₂ inhibited apoptosis induced by over ERS. The activated E₂ receptor can activate rapid estrogen receptor signaling pathways include PI3K-Akt, ERK1/2, JNK and p38-MAPK to inhibit ERS, and PI3K-Akt pathway may be the most important one. E₂ possibly prevent vascular endothelial cells by inhibition of apoptosis induced by ERS, and the mechanism of inhibiting ERS was mainly through the activated E₂ receptors activating PI3K-Akt pathway.