Abstract: Objective: To explore the effects of propofol and sevoflurane anesthesia on postoperatively cognitive function of aged patients in orthopedics. Methods: One hundred and twenty aged patients undergone orthopedic surgery were randomly divided into propofol and sevoflurane group( 60 cases， each group) . The propofol and sevoflurane group were anesthetized by injection 1 to 3 g /ml of propofol and inhalation 1% to 3% of sevoflurane after anesthesia induction，respectively. The serum levels of S100 and cognitive function in two groups were compared before and after operation. Results: Compared with preoperation， the scores of cognitive function in the propofol group decreased at 1，3 and 6 hours after operation( P ＜ 0. 01) ， the difference of cognitive function score beteween postoperative 1 hour and before operation has no statistic significance( P ＞ 0. 05) ，but its score at postoperative 6 days was higher( P ＜ 0. 01) . Compared with preoperation， the scores of cognitive function in the sevoflurane group decreased at 1，3，6， 24 and 72 hours after operation( P ＜ 0. 01) ， the differences of cognitive function score beteween postoperative 1 and 72 hours and before operation have no statistic significance( P ＞ 0. 05) . The scores of cognitive function in the sevoflurane group were lower than those in propofol group at 1，3，6， 24 and 72 hours after operation( P＜0. 01) . Compared with preopration， the postoperative serum levels of S100 protein in two groups were significant higher( P ＜0. 01)， the level of S100 in the sevoflurane group was significantly higher than those in propofol group( P ＜0. 01) . Conclusions: Both propofol and sevoflurane affect the patient's cognitive function， the effect of sevoflurane is the most.