Objective To explore the effects of dexmedetomidine on postoperative cognitive function after non-cardiac surgery in elderly patients by meta-analysis.Methods We searched Co-chrane Library,MEDLINE,EMbase,Ovid,Springer,China Biology Medicine,CNKI,VIP and WanFang Data for controlled clinical trials.All randomized controlled trials (RCT)that meet their standards of dexmedetomidine on postoperative cognitive function after non-cardiac surgery in elderly patients were collected. The meta-analysis was performed by Review Manager 5.3. Results Twenty-two trials with 1 713 patients were included in this meta-analysis.The results of me-ta-analysis showed that:Mini-mental state examination (MMSE)MD=2.99,95%CI (2.25,3.74) one day before operation,MD=1.66,95%CI (0.68,2.64)three days after operation,MD=1.52, 95%CI (0.55,2.49)seven days after operation,respectively (P <0.05);Perioperative dexmedeto-midine treatment was significantly associated with better neurocognitive performance in comparison with saline.Compared with normal saline group,the serum concerntrations of neuron-specificenolase, S100β protein, TNF-α and IL-6 were significantly decreased in dexmedetomidine group. Conclusion The present meta-analysis indicates that dexmedetomidine shows superiority over placebo in early postoperative neurocognitive function after non-cardiac surgery in elderly patients.