Changes of cerebral microcirculation and tissue cells after Hyperbaric Oxygen (HBO) exposure were observed in 136 gerbils with cerebral ischemia by observation of meningeal microcirculation pathological study in cerebral tissues and determination of Na, K-ATPase. It is indicated that HBO may be helpful in improving microcirculatory dynamics and other microcirculatory functions, and enhancing cerebral tissue cell activity and cell function, as well as increasing oxygen content. It is suggested that HBO (250 approximately 300kPa) may play a role in protecting vessel endothelial cells and nerve cells.