The purpose of the present study was to observe the proliferation of cerebral arterial smooth muscle cell (CASMC) induced by oxyhemoglobin (Oxyhb) and interfered by Adenovirus-mediate-PKGI (Ad-PKGI), and to investigate the potential regulative role of the PKGI gene in the molecule mechanism of cerebral vasospasm (CVS) after Subarachnoid hemorrhage (SAH). Tissue-sticking method was used for primary cultured rat CASMCs. Semi-quantitative reverse transcription and polymerase chain reaction (RT-PCR) and western blot were used to examine the PKGI mRNA and protein expressions after CASMC were transfected by Ad-PKG. The proliferation of CASMCs was determined by MTT assay and 3H-TdR incorporation. Ad-PKGI could be transfected into CASMCS and highly express. Oxyhemoglobin could stimulate the proliferation of CASMC; the value of 3H-TdR incorporation and the absorbance value of MTT increased and could block up after CASMC was transfected by Ad-PKG. The results suggested that the PKG signaling pathway might play an important role in CVS after SAH, and the PKG gene might be a target point of gene therapy.