Background　Postoperative cognitive dysfunction（POCD） commonly develops after major surgery in elderly patients which may affect patients' outcome. Regional cerebral oxygen saturation （rSO2） serves as a tool to evaluate cerebral oxygen supply-demand balance. It has been reported that intraoperative cerebral desaturation closely associated with POCD.　Objective　The aim of this review is to evaluate the correlation between rSO2 values and postoperative cognitive dysfunction.　Content　Near infrared spectroscopy（NIRS） allows continuous， noninvasive monitoring of rSO2. It is regarded as a promising， but not widely accepted technique to reduce POCD. This article reviewed the correlation between rSO2 values and postoperative cognitive dysfunction.　Trend　NIRS appears to be a new tool to predict central nervous system complications， however， futher study need to be conducted to evaluate the overall efficacy.