Objective To evaluate the effectivity of dexmedetomidine on the early postoperative quality of recovery in patients undergoing ambulatory knee arthroscopy under general anesthesia. Methods Patients scheduled for knee arthroscopy at the Day Surgery Center of the First Affiliated Hospital of Anhui Medical University between June and September 2024 were selected. According to the computer-generated random allocation, patients were randomly divided into the dexmedetomidine group (Dex group) and the saline control group (NS group). The Dex group received a continuous infusion of dexmedetomidine at a rate of 0.04 µg/(kg·h) until discharge, whereas the NS group was administered a comparable volume of saline. The primary outcome measure was the EuroQol Five-Dimensional Five-Level (EQ-5D-5L) score for health-related quality of life measured at the postoperative 24 hours. Secondary outcome measures included the Athens Insomnia Scale score on the night of surgery and the incidence of adverse reactions such as nausea and vomiting within 24 hours postoperatively. Results A total of 60 patients were included, with 30 patients in each group. There were statistically significant differences in the EQ-5D-5L health scores at the postoperative 24 hours (0.857±0.081 vs. 0.721±0.098) and the Athens Insomnia Scale scores [2.00 (2.00, 3.00) vs. 4.00 (3.00, 5.25)] on the night of surgery between the Dex group and the NS group (P<0.05). The difference in the incidence of postoperative nausea and vomiting between the two groups was not statistically significant [1 case (3.3%) vs. 5 cases (16.7%); χ2=1.667, P=0.197]. No adverse reactions such as bradycardia, hypotension, urinary retention, respiratory depression, dizziness and lethargy occurred in both groups. Conclusion Dexmedetomidine can significantly improve the early postoperative quality of life and sleep in patients undergoing ambulatory knee arthroscopy, thereby facilitating early postoperative quality of recovery.