The purpose of this study is to confirm the angiogenic effect of bFGF gene therapy in rabbit ischemic hind limb model and to disclose the mechanism of basic fibroblast growth factor (bFGF) angiogenic effect. It is well known that bFGF gene has angiogenic effect. However, the underlying mechanism of angiogenic effect of bFGF gene therapy was still not known exactly. We investigated the underlying mechanism by molecular biologic technique. Recombinant gene (Ad/bFGF) was constructed by using human bFGF gene and adenovirus vector by homologous recombination technique. The efficiency of transfection and the effect on the endothelial proliferation and migration was confirmed in vitro. We could find marked increase of vascular endothelial growth factor (VEGF), as well as bFGF in In vitro culture media. So, we hypothesized that these two additional factors might affect the angiogenesis. We investigated the angiogenic effect by bFGF, VEGF, and conditioned media produced by bFGF gene treatment. Phosphorylation inhibition study demonstrated that the angiogenesis after bFGF gene transfer was significantly affected by the Raf, and ERK1/2 activation Tyr340/341 was activated by VEGF and conditioned media, but not by bFGF. And also, Ser338 was activated by bFGF and conditioned media, but not by VEGF. Both factors finally activated Raf. So, it revealed that bFGF gene treatment to vascular endothelial cells showed angiogenic effect under dual activation mechanism of Raf-ERK1/2 pathway by both bFGF and VEGF. This finding was confirmed by MTT assay, and endothelial cell proliferation study. In conclusion, the angiogenic effect of bFGF intramuscular gene therapy in rabbit ischemic hind limb model was confirmed. And the Western blot immunostaining study showed that Raf-MEK1/2-ERK1/2 signal transduction pathway directed by dual action mechanism of bFGF and VEGF might be involved in the angiogenic process of bFGF gene therapy.