The scope of this research lies in the effects of indocyanine green (ICG) on the near-infrared optical properties and optical coherence tomographic image of cerebral blood vessel in vivo in rats. The skulls of SD rats were opened under nembutal anesthesia to expose and mark the middle cerebral artery. The reflectance spectra of middle cerebral artery were monitored by Vis/NIR spectrometer and the optical attenuation coefficients of middle cerebral artery were detected by optical coherence tomography (OCT) when indocyanine green was administrated intravenously through tail veins. It was shown that the reflectance spectra of middle cerebral artery could provide guidance for OCT image, where characteristic changes appeared around 800 nm, an absorption peak of indocyanine green. Additionally, significant difference (p<0.01) was observed between the optical attenuation coefficients of middle cerebral artery with and without indocyanine green, which were 24.692±1.471 and 15.088±1.602, respectively. It was concluded that indocyanine green, as an optical contrast agent to enhance detection of cerebral artery by the reflectance spectra and OCT imaging, has the potential for monitoring and imaging of cerebral blood vessels.