Abstract: After entering human body through respiration, air pollutant PM_2.5 can cause pulmonary diseases and cardiovascular diseases, and are related to brain aging, memory decay, and some neurodegenerative diseases. In recent years, lots of studies have illustrated that PM_2.5 can enter the systemic circulation through the alveolar blood-air barrier, nasal epithelial barrier, or transferring to the olfactory nerve, reach the brain, and then pass through the blood-brain barrier, thus causing damage to the structure and function of the central nervous system. PM_2.5 can damage the central nervous system and the homeostasis of blood lipids by changing DNA methylation level, activating glial cells, oxidative stress, and inflammatory response, and damaging synapses or other organelle structures, thus having a more significant impact on systemic lipid metabolism. Lipids are the main components of the brain and play an essential role in the functioning of the nervous system. In brain tissues, there is a relationship among PM_2.5 exposure, lipid level changes, and nervous system diseases, but the specific mechanisms of lipid metabolism disorder in neurodegenerative diseases and injuries caused by PM_2.5 have not been elucidated. This article focused on the relationship among PM_2.5, lipid metabolism disorder, and central nervous system diseases, and the potential mechanisms of brain lipid metabolism disorder and brain function damage caused by PM_2.5.