Neurodegenerative disease is a kind of degenerative diseases of the central nervous system that seriously endanger human health. The complement 3 (C3)-complement 3a receptor (C3aR) pathway is one of the important pathways for classical complement cascade activation. A large number of studies have shown that the C3-C3aR pathway can mediate and regulate the interaction of astrocyte-microglia axis in neurons, resulting in function changes in central nervous system. In addition, studies in recent years have found that the C3-C3aR pathway is closely related to the occurrence and progress of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, stroke, and epilepsy. This article reviews the progress of C3-C3aR pathway and discuss the role of C3-C3aR pathway in several important neurodegenerative diseases, and it provides a new idea fo treatment of these diseases.