Abstract: Objective:To study the influence of different anesthesia methods (plexus cervicalis block and general anesthesia) on early postoperative cognitive function in elderly patients who suffer from thyroid disease. Methods:Sixty patients more than 65years old with thyroid disease were randomly given general anesthesia ( Group A,30cases ) and plexus cervicalis block ( Group B, 30cas-es ). The assessment of postoperative cognitive function refers to the scores achieved in the neuropsychological testing using the mini mental state examination ( MMSE ) by the same psychiatrist on the day before the operation and the first 12and 24h after the surgery. Patients with psychosis or neuropathy were excluded, as well as patients who take medicines that affect nervous system function long-term were also excluded. The aggregate MMSE score is 30. The standard deviation of the patient MMSE before the operation was calculated and compared with those of the first 12and 24h after the surgery. Results:The MMSE scores were lower in Groups A and B within the first 12h after surgery than that before the operation ( P < 0.05). The incidence of POCD in Group A within the first 12and 24h after surgery ( 16.7% and 3.3% ) was not statistically different from that in Group B (10.0% and 3.3%;P > 0.05). Conclusion: There is a higher incidence of early POCD after thyroid surgery, especially among patients more than65years old. Compared with the patients who underwent the plexus cervicalis block, the incidence of POCD among the elderly who underwent thyroid surgery under general anesthesia was lower.