【Abstract】 Background Postoperative cognitive dysfunction （POCD） is one of the complications of surgery, which is firstly reported as a complication with relative high incidence occurred in elderly patients undergoing cardiac surgery. Patients suffering POCD represent declined cognitive function, and with prolonged rehabilitation phase. On the other hand, with the increasing number of aged patients in operation room, elucidating the mechanism underlying POCD become more urgent. Studies about the POCD etiology, pathogenesis in recent years have made much progress. However, the development mechanisms of POCD are not yet clarified and the cause of POCD is still controversial. Objective The review summarized the recent studies on POCD in order to provide some clues for further understanding and studies. Content Different pathogenesis mechanisms, such as anesthesia, aging and surgery trauma, have been applied to explain the occurrence of POCD. Among these hypothesises，the neuroinflammation occurring in the central nervous system (CNS) has been accepted by most researchers as a major cause of POCD. A lot of researches have been conducted to explore the causes of neuroinflammation and the pathophysiological changes it results in. Trend In view of recent studies, single mechanism is not enough to elaborate the incidence of POCD. Much more studies should be carried out to elucidate the mechanisms underlying POCD, besides the neuroinflammation mechanism may remain to be a focus.