Abstract： Objective To investigate the effect of lipopolysaecharide (LPS) on ischemia/reperfusion (I/R) injury of liver and the protective effect of isoflurane (ISO) pretreatment on such injury in rat. Methods Thirty-two male Spregue-Dawley(SD) rats were randomly assigned to 4 groups: Sham group, only receive anesthesia and laparotomy: I/R group;I/R+LPS group, with 1 hour of hepatic isehemia and 4 hours of reperfusion, and LPS was given at the beginning of reperfusion;ISO group, received ISO pretreatment for 0. 5 hour, then 1 hour of hepatic isehemia followed by 4 hours of reperfusion and LPS given at the beginning of reperfusion. The pathological changes in the liver tissue were assessed. Alanine aminotransferase (ALT),aspartate aminotrasferase (AST), the myeloperoxidase (MPO) activity in liver tissue, hepatic and serum tumor necrosis factor-α (TNF-α) were determined. Results Compared with Sham group, ALT, AST,TNF-α in serum and MPO activity in liver tissue, hepatic and serum TNF-α were increased significantly in all injury groups (all P＜0. 01). Compared with ISO group alone, hepatic I/R combined with LPS resulted in severer liver injury, with the levels of ALT, AST in serum, MPO activity in the liver tissue, and hepatic and serum TNF-α level were all increased (all P＜0.05). Compared with I/R+LPS group, both the liver injury and inflammatory reaction were significantly reduced in I/R group (P＜0. 05 or P＜0.01). Conclusion LPS injection during reperfusion results in severer liver injury and inflammatory reaction after hepatic I/R in rats.ISO pretreatment for 30 minutes might reduce the inflammatory reaction and live injury induced by hepatic I/R combined with LPS.