摘要Microglia, the main innate immune cells in the central nervous system, takes part in lots of physiological and pathological processes in the brain.It not only maintains brain homeostasis but also participates in the process of brain injury and repair under pathological conditions.In developmental brain, microglial synaptic pruning may eliminate "weaker" synapses and retain "stronger" synapses.Synaptic pruning also plays a vital role in mediating the formation of neural circuit under physiological condition, contributes to cell and myelin debris clearance, promotes maturation of oligodendrocytes, which surround the bare axon to form myelin sheath, and helps the regeneration of neurons and synapses.Recently, increasing number of studies on microglial synaptic pruning has advanced our understanding of the underlying mechanism for synaptic pruning and its relevant physiological functions.Here, we reviewed microglial synaptic pruning function and its potential regulatory mechanisms in brain under physiological and pathological conditions.