Abstract： Objective To explore the effects of nuclear factor kappa B (NF-KB) in rabbit immune-complex-induced acute lung injury (ALI). Methods Thirty rabbits were randomly divided into 5 groups,including N, M2h, M4h, M6h and MSh groups. N group was the normal control group. M2h, M4h, M6h and M8h groups were ALI model groups. The rabbits in the N group were treated with intra-tracheal injection of 1 ml normal saline and another dose of normal saline (2 ml/kg) injected via the marginal ear vein. The rabbits in the model groups were injected intra-trachea with bovine serum albumin antibody(anti-BSA) 1 ml and injected with bovine serum albumin(BSA) via marginal ear vein at dose of 2 ml/kg. Then the rabbits in the N group were killed at 8 h. The rabbits in M2h, M4h, M6h and M8h groups were killed at 2 h, 4 h, 6 h and 8 h respectively. The maleic dialdehyde (MDA)concentrations, the superoxide dismutase (SOD) activity, the protein concentrations in bronchoalveolar lavage fluid (BALF) and lung wet/dry weight ratio (W/D) were measured. The cellular distribution of NF-κB P65 in lung tissues was determined by immunohistochemistry. Results The concentrations of MDA, protein in BALF and W/D of lung tissue inM2h, M4h, M6h, M8h groups in creased significantly as compared with those in the N group. On the contrary,the activity of SOD in BALF in the model groups decreased significantly as compared with that of the N group. Increased expression of NF-κB in inflammatory cells was found in lung tissues from the model groups.The number of positive cells in M2h, M4h, M6h, M8h groups [(26. 5±5.9), (39. 9±6. 9), (51.0±6.3), (58.0±5.3)]increased significantly as compared with that in the N group [(7.4±1.9), (t =8.73-25. 33, P <0. 01)]. Conclusions Immune-complex-induced ALI animal models can be established by intra-tracheal injection of anti-BSA serum and venous injection of BSA. NF-κB may play an important role in immune-complex-induced ALI by inflammatory mechanism.