Objective To investigate the effect of pentoxifylline on hepatic NF-κB activity of nonalcoholic steatohepatitis(NASH) in rats. Methods Rats fed with a standard diet for one week were randomly divided into four groups： the control group(n=10), the 12weekmodel group(n=10), the 16weekmodel group(n=10) and the PTX treatment group(n=10). Two model groups and the PTX treatment group were fed with a highfat diet and the control group with a standard diet.After 12 week, the 12weekmodel group were sacrificed and the treatment group were given PTX ［16mg/(kgI>&#/I>8226;d)］ by intragastric administration. Then all the remaining rats were sacrificed at the end of the 16th week. The expressions of NF-κB and inhibitor κB-α(IκB-α) proteins in livers were analyzed by immunohistochemistry. The expression of NF-κBp65 protein was determined by Western blotting. Results The expression of NF-κBp65 increased significantly in the model groups and the PTX treatment group (vs the control group, P<0.05) but decreased in the PTX treatment group (vs the model groups);