Objective Overexpressing gax gene in vascular smooth muscle cells(VSMC) mediated by adenovirus transfection.Methods Replication defective adenovirus type 5 (Ad5) vector encoding the rat gax gene (AdCMV gax) was constructed via site specific recombination and amplified in 293 cells. The resulting adenovirus was purified for a high viral titer. The expression of gax mRNA and protein was evaluated by a series of methods such as reverse transcription polymerase chain reaction (RT PCR), flow cytometry and immunocytochemical technique after gax gene was transferred to VSMCs. Results When AdCMV gax was transfected to VSMCs, the expression of gax protein increased significantly in VSMCs, and reached 80% in 24 hours. High expression of gax protein could keep for over 5 days. Before AdCMV gax was transfected to VSMCs, gax mRNA and protein could be down regulated by platelet derived growth factor (PDGF) BB. After AdCMV gax was transfected to VSMCs, the level of gax expression was significantly higher than that before transfection, and no correlation with the stimulation of PDGF BB.Conclusions gax gene can be transfected to VSMC by AdCMV gax and translated to protein, which is advantageous to exploring the effects of gax gene on biological behaviour of VSMC.