Objective To investigate the relationship between oncogenic H-RasV₁₂ overexpression/activation and the autophagic activity by observing the effect of Ras overexpression on autophagic activity in human fibroblast cells. Methods Human BJ fibroblast cells were transfected with H-RasV₁₂ or control vector, and then the cellular responses to H-RasV₁₂ overexpression were analyzed by observing the morphology, cell growth curve, senescence-associated β-Gal staining, Western blotting analysis, flow cytometry, and suppression of autophagy-related protein 5 (ATG5) by siRNA. Results Compared with control group, BJ cells overexpressing H-RasV₁₂ developed prominent premature senescence and inhibited autophagic activity, as manifested by significant accumulation of p62 and light chain 3Ⅱ (LC3Ⅱ). The autophagy inhibition by H-RasV₁₂ remained stable during the study period; the apoptosis rate was increased in H-RasV₁₂ overexpressing BJ cells compared with that in the control cells. Suppression of ATG5 by siRNA led to more severe senescence in Ras-overexpressing BJ cells. Conclusion Our results suggest that the autophagy activity is inhibited in human fibroblast cells stably overexpressing oncogenic H-RasV₁₂, and the inhibition is in the later stage of autophagy, which may be related to H-RasV₁₂-related tumorigenesis.