To investigate the inhibiting effect of β-Aescin on nuclear factor-κB (NF-κB) activation and the expression of tumor necrosis factor-α (TNF-α) protein after traumatic brain injury (TBI) in the rat brain, 62 SD rats were subjected to lateral cortical impact injury caused by a free-falling object and divided randomly into four groups: (1) sham operated (Group A); (2) injured (Group B); (3) β-Aescin treatment (Group C); (4) pyrrolidine dithocarbamate (PDTC) treatment (Group D). β-Aescin was administered in Group C and PDTC treated in Group D immediately after injury. A series of brain samples were obtained directly 6h, 24 h and 3 d respectively after trauma in four groups. NF-κB activation was examined by Electrophoretic Mobility Shift Assay (EMSA); the levels of TNF-α protein were measured by radio-immunoassay (RIA); the water content of rat brain was measured and pathomorphological observation was carried out. NF-κB activation, the levels of TNF-α protein and the water content of rat brain were significantly increased (P＜0.01) following TBI in rats. Compared with Group B, NF-κB activation (P＜0.01), the levels of TNF-α protein (P＜0.01) and the water content of brain (P＜0.05) began to decrease obviously after injury in Groups C and D.β-Aescin could dramatically inhibit NF-κB activation and the expression of TNF-α protein in the rat brain, alleviate rat brain edema, and that could partially be the molecular mechanism by which β-Aescin attenuates traumatic brain edema.