Objective:To explore the safety and feasibility of adrenal tumor resection under day surgery mode for the treatment of unilateral primary aldosteronism (UPA).Methods:The clinical data of 83 patients who underwent adrenalectomy for the treatment of UPA from January 2020 to January 2023 were retrospectively analyzed. There were 42 males (50.6%)and 41 females (49.4%), age (49.0±12.3)years old. Body mass index (25.4±3.6)kg/m 2. There were 17 patients with diabetes, 58 patients with preoperative hypertension, and the duration of hypertension was 8.2(1, 15)years. Systolic blood pressure was 151.8(137.0, 160.0)mmHg (1 mmHg=0.133 kPa), and diastolic blood pressure was 97.4(87.0, 107.0)mmHg. 20 cases had severe preoperative hypokalemia, with preoperative blood potassium levels of (2.9±0.6)mmol/L. The ratio of preoperative plasma aldosterone to renin activity was 54.1(13.0, 77.2). Tumors were located on the left side in 47 cases (56.6%)and on the right side in 36 cases (43.4%). The maximum diameter of the tumor is 1.5(1.0, 1.7)cm. Patients diagnosed with unilateral primary aldosteronism were included, and patients diagnosed with adrenal pheochromocytoma, adrenal malignancy, or severe cardiovascular disease that cannot tolerate surgery were excluded. The patient was admitted to the hospital on the same day, underwent surgery on the same day, and was evaluated after extubation within one day after surgery. The patient had no fever or lower back pain after surgery, was able to freely get out of bed, and had no obvious abnormalities in blood routine, electrolyte and other test indicators. The patient was discharged from the hospital and received continuous care outside the hospital. The patient was guided to undergo regular outpatient follow-up. Evaluate the efficacy using the Primary Aldosterone Hyperaldosteronism Surgical Outcome (PASO)criteria. Results:The patients had a mean length of hospital stay of 43.0(40.3, 44.6)hours, an operation time of 89.6(70.0, 103.0)minutes, and an operation cost of 23 820.2 (21 150.8, 24 948. 3)yuan. The postoperative free position time was 29.5(20.8, 39.7)hours, the postoperative time for fluid placement of the diet was 25.2(20.1, 27.8) hours, and 42.2(37.9, 41.9)hours of postoperative drain removal. The overall postoperative clinical remission rate was 85.5%. There were four postoperative complications, accounting for 4.8% of cases. These included two cases of interosseous vein thrombosis, one case of delayed healing, and one case of peritoneal rupture. No case of readmission was reported within 30 days.Conclusions:UPA adrenal tumour resection in ambulatory mode is safe and effective when strict inclusion and exclusion criteria are followed, adequate preoperative preparation is carried out, and expert physician assessment is provided.