Background Cognitive decline in elderly persons following anesthesia has been reported in the literature for over a century. Postoperative cognitive dysfunction (POCD) is a decline in cognitive function from preoperative levels. However cognitive difficulties are also common in elderly persons who do not undergo anesthesia. Most studies about COPD ignored many other causes of obscure cognitive decline. The methodological problem for research in POCD may confound potential neurotoxicity of anesthetics. Objective Summarize the neuropsychological concepts of POCD studies. Content： According to the DSM-Ⅳ, POCD is a special type of mild cognitive impairment(MCI) , which has been described as a transitional state between normal aging and dementia. Most POCD studies claimed they have excluded patients with pre-existing cognitive, psychiatric, or central nervous system disorders, while patients with obscure cognitive decline such as MCI, normal aging and depression were included, which may have led to an overestimation of anesthetic effects. New pathophysiolgy and neuropsychological tests, which come along with research progress in these neuropsychological concepts, become an inspiration of COPD studies. Trend Concerning to the complicated neuropsychological tests and the methodology used to analyze the tests about obscure cognitive decline, different expertise’s collaborations between neuropsychiatrists and anesthesiologists were urgently needed.