Tanshinone IIA (Tan IIA), an active component derived from Salvia miltiorrhiza root, has been used to treat various ischemic cardiovascular and cerebrovascular diseases. However, its impact on hepatic ischemia/reperfusion (I/R) injury remains unclear. Here, we addressed this issue by using a 90-minute partial liver ischemia model. Mice were administered Tan IIA intragastrically for 3 days before ischemia and were assessed for liver damage 6-h after reperfusion. Tan IIA pretreatment significantly inhibited serum aminotransferases and proinflammatory cytokine levels along with reduced inflammatory infiltration and liver damage. Mechanistic studies revealed that Tan IIA suppressed TLR4 expression in nonparenchymal cells (NPCs) and induced heme oxygenase-1 (HO-1) production in both parenchymal and NPCs. Moreover, the phosphorylation of AKT and ERK1/2 in the liver was enhanced, while the phosphorylation of JNK, p38 and p65 was suppressed. These results suggest Tan IIA can suppress TLR4 signaling which then enhances HO-1 expression along with reduced proinflammatory cytokine expressions in the liver, and Tan IIA could be a useful candidate drug in clinic for prevention and treatment of hepatic I/R injury.