Reactive oxygen species （ROS） were cellular metabolism byproducts，and they play an important role in the development and progression of cerebral ischemia. ROS elimination was usually recognized as an important way of neuroprotection in previous studies. However，recent studies have shown that ROS not only mediate brain tissue damage after ischemia，but also promote tissue repair as signal molecules. Certain amount of ROS can promote cell proliferation，migration，activate angiogenesis-related pathways，and facilitate angiogenesis. Therefore，comprehensive understanding of the role of ROS in the dynamic process after cerebral ischemia，and rational regulation of ROS content in cerebral ischemia can promote angiogenesis in damaged areas，which is of great significance for recovery of blood supply and protection for neuron function.