Objectives To investigate the clinical efficacy of endoscopic transsphenoidal reoperation for recurrent or residual pituitary adenoma. Methods A total of 69 patients with pituitary adenoma admitted from January 2015 to June 2018 were retrospectively analyzed. Operation time， postoperative length of stay， operation complication rates and resection rates were compared for both first-time operation and reoperation groups. Results There were no statistically significant differences in resection rates and operation time across the two groups（ P ＞ 0.05）. However， the postoperative length of stay was significantly longer in reoperation group than that of the first-time operation group［ （13.30±6.81）d vs（ 9.60±3.55）d；t=2.16， P＜0.05］. There was also a significant difference in operation complication rates across the two groups， characterized by an increase in the occurrence of cerebrospinal fluid leakage， intracerebral infectious and diabetes insipidus in the reoperation group（ P＜ 0.05）. Conclusions The total resection rate of recurrent and residual endoscopic transsphenoidal pituitary adenomas is not significantly different from that of the first operation， but the incidence of complications increases significantly， the length of hospitalization after operation prolongs， and the complexity and difficulty of reoperation in resecting tumors and protecting important adjacent anatomical structures are significantly higher than those of the first operation.