【Abstract】 Objective The effects of overexpression of wild type phosphatase and tensin homology deleted on chromosome Ten（PTEN）on extracellular signalregulated kinase (ERK) signal transduction was investigated in activated rat hepatic stellate cell (HSC) in vitro. Methods Using transient transfection technique, adenovirus as a carrier, wildtype PTEN gene was transduced into cultivate activated rat HSC in vitro. Using Western blot and realtime fluorescent quantitation PCR, the expressions of PTEN and ERK1 were detected in HSC. And the expression of phosphorylated ERK (pERK) of HSC was determined using Western blot. Results The exogenous wild type PTEN gene was successfully transduced into activated rat HSC in vitro. The expression of pERK was significantly downregulated, P＜0.05, but there were no significant differences in the expression of ERK1 at both transcriptional and translational levels in activated HSC, P＞050. Conclusion Through inhibiting the phosphorylation of ERK, the ERK signaling transduction is negatively regulated by the overexpression of wildtype PTEN in activated rat HSC in vitro.