Objective: To investigate the impact of frailty-originated, evidence-based early activity training on postoperative delirium in patients who have undergone brain tumor resection.Methods: A randomized controlled trial was conducted at the Second Affiliated Hospital of Zhejiang University School of Medicine, from July 2019 to June 2020. Data on the patients' general information, incidence and duration of delirium, duration of hospital stay, and activities of daily living were collected. From the first day after surgery, the patients were randomly assigned to either the traditional care group or the frailty-originated reha-bilitation towards intracranial tumors using distinct evidence (FORTITUDE) group. Non-parametric, chi-square, and log-rank tests were used to compare the onset time and duration of postoperative delirium and activities of daily living performed by the participants between the two groups. Results: In total, 291 patients, 150 and 141 in the control group and FORTITUDE group, respectively, participated in the study. Patients in the FORTITUDE group had a lower incidence of postoperative delirium (15.6% vs. 28.7%, P = 0.007), delayed onset of delirium (Z = -2.108, P = 0.035), shorter duration of postoperative delirium (& chi;2 = 26.67, P < 0.001), shorter hospital stay (Z = -2.037, P = 0.042), and higher scores in the activities of daily living one week (Z = -2.304, P = 0.021) and one month (Z = -2.724, P = 0.006) after surgery than in the control group.Conclusions: The FORTITUDE program was safe and effective in reducing the incidence and duration of post-operative delirium and improving the quality of life of patients who underwent brain tumor resection.