Ｏｂｊｅｃｔｉｖｅ　Summarizing the related published articles about depth of anesthesia and postoperative cognitive dysfunction(POCD) in noncardiac surgical patients, and observing the effect of depth of anesthesia on short-term or long-term POCD.　Methods　The literature searching indentified 352 articles related to the topic from PubMed, The Cochrane Library, EBSCO, Springer, Ovid, National Knowledge Infrastructure(CNKI), Wanfang data library and VIP network(by February 2016). As our aim tended to focus on the effect of depth of anesthesia on POCD and S100β protein level, twenty randomized controlled trials were finally included and the Meta analysis was performed using RevMan 5.3 software.　Results　A total of 2665 patients from 20 randomized controlled trials(RCT) was enrolled. The Meta analysis showed that, deep anesthesia decreased POCD incidence significantly compared with light anesthesia postoperative day 1[odds ratio(OR)＝0.31, 95%CI: 0.24-0.40], from day 3 to 5(OR＝0.35, 95%CI: 0.24-0.51), day 7 (OR＝0.45, 95%CI: 0.27-0.74), or within the 1st to 3rd month(OR＝0.66, 95%CI: 0.45-0.99) after surgery. S100β protein level in patients receiving deep anesthesia was much lower than that in patients receiving light anesthesia[mean deviation(MD)＝-270.29, 95%CI: -295.81- -244.77] on postoperative day 1.　Conclusions　Deep anesthesia can significantly reduce the incidence of POCD within postoperative 7th day, 1st to 3rd month after surgery. Serum S100β protein level which may be closely related to POCD incidence could be reduced by deep anesthesia on postoperative day 1.