Objective To investigate the effect of dexmedetomidine combined with ropivacaine on postoperative sleep quality in patients undergoing upper abdominal surgery following Oblique Subcostal Transversus Abdominis Plane Block （OSTAPB）. Methods A total of 140 patients who underwent gastric surgery at the Affiliated Hospital of Xuzhou Medical University between September 2024 and November 2024 were enrolled. According to the random number table method， they were randomly allocated into two groups： the simple subcostal transversus abdominis plane block group （Group A） and the dexmedetomidine combined with subcostal transversus abdominis plane block group （Group B）， with 70 patients in each group. The study compared the Asymptomatic Sleep Disturbance Scale （AIS） scores and Self?rating Anxiety Scale （SAS） scores on the night before surgery， AIS scores on the night after surgery and the following day， the amount of remifentanil used during surgery， and the cumulative number of patient?controlled analgesia （PCA） button presses within 3 days postoperatively. Additionally， the Numeric Rating Scale （NRS） pain scores at 2 h， 6 h， 12 h， 24 h， and 48 h post?surgery， as well as the Quality of Recovery?15 （QoR?15） scores on the night of surgery and the second day post?surgery， were evaluated. Results There were no significant differences in anxiety levels or subjective sleep quality scores between the two groups prior to the operation （P > 0.05）. Additionally， there was no significant difference in the usage of remifentanil between Group A and Group B （P > 0.05）. The NRS scores for pain differed significantly between the two groups within the first 48 hours post?operation （P < 0.05）； however， no significant difference was observed in NRS scores between the two groups after 24 hours during rest. Furthermore， the number of patient?controlled analgesia （PCA） activations in Group B was significantly lower than that in Group A at 12 hours post?operation （P < 0.05）. Lastly， both the QoR?15 and sleep quality were significantly higher in Group B compared to Group A （P < 0.05）. Conclusion Dexmedetomidine combined with ropivacaine for subcostal transversus abdominis plane block not only provides superior postoperative analgesia compared to ropivacaine alone but also enhances patients' sleep quality and recovery quality on the night following surgery， thereby contributing to improved overall postoperative recovery.