Background　Melatonin penetrates the blood-brain barrier and binds with brain neurons， and protects nervous system through antioxidant， anti-inflammation and anti-apoptosis effects. Recent studies have focused on the influence of exogenous melatonin on learning and memory， neural degenerative disease and postoperative cognitive dysfunction （POCD）， and relevant mechanisms.　Objective　To provide basis for further investigation on protective effects of melatonin on central nervous system （CNS） pathology and perioperative application by reviewing recent investigations on neuroprotection of CNS.　Content　The influence of melatonin on memory， long term potentiation and neuronal plasticity in hippocampus and other brain regions， and underlying mechanisms including influence of neurotransmission system and inhibition of oxidative stress， inflammation and cellular apoptosis were introduced. The protective effects of melatonin on neurodegerative disease and POCD caused by multiple factors were discussed.　Trend　The mechanisms in learning and memory， cognitive dysfunction of the aged and POCD are still unclear， but the same neurotransmission pathway and pathology may be involved. As an antioxidant and circadian rhythm regulator， melatonin has wide prospects for investigation and values for clinical application.