Abstract: Objective To study the effect of carboxylesterase 1（CES1） on stenosis and inflammatory reactions in rats after carotid artery injury. Methods Rats were randomly divided into CES1 group,non-virus loading group and blank control group.Rats in CES1 group were injected with slow virus vectors containing CES1 via the tail vein on days 0,1,and 2 after the common carotid artery injury model was established.Rats in non-virus loading group were injected with slow virus vectors containing no CES1 after carotid artery injury.Rats in control group underwent sham operation.Carotid artery tissue samples were taken on day 14 after carotid artery injury.Hyperplasia of carotid artery intima was assayed with H＆E staining.Expression of TLR-4 was detected by Western blot and RT-PCR,respectively,with immunohistochemical staining. Results Over-expressed CES1 could significantly inhibit hyperplasia of carotid artery intima,improve inflammatory reactions and reduce stenosis.RT-PCR and Western blot showed that over-expressed CES1 could down-regulate the expression of TLR-4 in carotid artery intima. Conclusion Over-expressed CES1 can inhibit the inflammatory reactions and improve stenosis after carotid artery injury by down-regulating the expression of TLR-4.