Cholecystokinin(CCK) is one of the first discovered gastrointestinal hormones and one of the most abundant neuropeptides in the brain. CCK , as a neurotransmitter or modulator, is involved in many different biological processes. This review presents an updated overview of the anatomical distribution of CCK in brain, the changes of cerebral CCK gene expression and CCK level during brain injury, the neuroprotective effects of CCK and its underlying mechanisms.