Objective: To explore the effects of intraspinal anesthesia with dexmedetomidine and nalbuphine on intraoperative hemodynamics and postoperative emergence agitation in elderly patients undergoing knee arthroplasty (KA). Methods: A total of 66 patients were enrolled and randomly divided into observation group (dexmedetomidine combined with nalbuphine) and control group (nalbuphine) between January 2024 and June 2025. The incidence of agitation, analgesic and sedative effects, hemodynamics immediately after entering the operating room (T0), at 5min after anesthesia (T1), 30mi after anesthesia (T2) and end of the surgery (T3), stress factors, inflammatory factors and adverse reactions were compared between the two groups. Results:? The observation group had shorter first straight leg raise time, first ambulation time, and hospital stay compared to the control group (P<0.05). The observation group has a lower overall incidence of agitation (18.18% vs 3.03%, P<0.05). Compared with control group, score of visual analogue scale was lower, and score of Ramsay sedation was higher in observation group (P<0.05). At T1, T2 and T3, mean arterial pressure and heart rate in observation group were lower than those in control group (P<0.05). After surgery, levels of stress factors and inflammatory factors in observation group were lower than those in control group (P<0.05). The incidence of adverse reactions showed comparable rates across both groups (12.12% vs 24.24%, P>0.05). Conclusion: Dexmedetomidine combined with nalbuphine can effectively stabilize hemodynamics and reduce the risk of emergence agitation, with good safety.