UCH-L1 is abundantly expressed in brain which possesses ubiquitin hydrolase activity, ubiquitin ligase activity and the effect of monomeric ubiquitin stabilizing. UCH-L1 is critical for the normal morphology and function of the synapses, which can rescue the LTP deficit and impaired memory induced by β-amyloid protein (Aβ). In addition, the I93M mutation in UCH-L1 is associated with familial Parkinson's disease (PD) while the S18Y polymorphic variant of UCH-L1 is associated with a specific antioxidant protective function in neurons. By researching the structure, function and the mechanism in the nervous system of UCH-L1, hopes to provide a concept or a method to treat neurodegenerative diseases such as AD and PD.