Abstract: Objective To evaluate the effect of electrical impedance tomography (EIT)-guided personalized positive end-expiratory pressure (PEEP) setting on postoperative pulmonary complications in elderly frail patients undergoing robot-assisted prostate cancer radical surgery. Methods A total of 66 patients aged ≥65 years with a frailty score (Fried Frailty Index) ≥3 who were scheduled for robot-assisted prostate cancer radical surgery were selected. The patients were randomly divided into two groups (n=33): an EIT-guided personalized PEEP group (group I) and a fixed PEEP group (group P). Patients in group I received personalized PEEP settings based on EIT results, while those in group P were set to a fixed PEEP of 5 cmH₂O (1 cmH₂O=0.098 kPa). Arterial blood samples were collected before pre-oxygenation (T1), at post-intubation 5 min (T2), at post- pneumoperitoneum 30 min (T3) and 1 h (T4), and at post-extubation 15 min (T5), to measure arterial oxygen partial pressure (PaO₂) and oxygenation index (OI). Their airway peak pressure, plateau pressure, driving pressure, and dynamic compliance were recorded at post-PEEP titration 5 min (t1), 30 min (t2) and 1.5 h (t3), and before extubation (t4). The time to extubation, length of hospitalization stay, and incidence of postoperative pulmonary complications within postoperative seven days were recorded. Results During surgery, group I showed increases in airway peak pressure, plateau pressure, and dynamic compliance and decreased driving pressure, compared with group P (P<0.05). From T2 to T4, increased PaO₂ and OI were observed in group I, compared with those in group P (P<0.05), while there was no statstical difference between the two groups at T5 (P>0.05).There was no statstical difference between the two groups in the incidence of postoperative pulmonary complications or the length of postoperative hospitalization stay (P>0.05). Group I showed shorter time to extubation than group P, with statistical differences (P<0.05). Conclusions In elderly frail patients undergoing robot-assisted prostate cancer radical surgery, EIT-guided personalized PEEP dose not significantly reduce the incidence of postoperative pulmonary complications within post-operative seven days, but it does improve intraoperative oxygenation and respiratory mechanics.