Background: Microglia plays a major role in the early postoperative central inflammatory response. The hallmark of brain inflammation is the activation of microglia cells which associated with the Toll-like receptor 4(TLR4). Central inflammatory cytokines affect the central receptors or neurotransmitters function through a variety of channels, thus affecting learning and cognitive abilities. Objective: Investigative the role of TLR4 in the inflammatory response of the microglia and the relationship with cognitive function. Content: Reviewed mainly from four aspects: the relationship of TLR4 with microglia, the microglia central relationship of inflammation, inflammation and TLR4 on cognitive. Trend: Microglia plays a major role in the inflammation of the central nervous system (CNS). TLR4 acted as a regulator in microglia activation and inflammatory response, but the roles of TLR4 in microglia of the central inflammatory response and cognitive are unclear.