Objective To assess the prophylactic analgesic effects of dexmedetomidine in combination with dezocine in the hypertensive elderly patients undergoing thoracoscopic surgery. Methods Eighty patients of both genders (age, 65-80 years) scheduled for elective thoracoscopic lobectomy under general anesthesia were randomly divided into 4 groups:dexmedetomidine group (DEX group), dezocine group (DEZ group), dexmedetomidine+dezocine group (DD group), and control group (C group). Patients in DEX group received intraoperative intravenous infusion of dexmedetomidine at 0.4 μg/(kg·h). In DEZ group, dezocine 0.1 mg/kg was injected intravenously 15 min prior to the induction of anesthesia and at the time of suturing. In DD group, dezocine 0.1 mg/kg was injected intravenously 15 min prior to the induction of anesthesia, followed by intraoperative intravenous infusion of dexmedetomidine 0.4 μg/(kg·h) and subsequent intravenous injection of dezocine at the time of suturing. Normal saline of equal volume was administered in C group. Patient-controlled intravenous analgesia (PCIA) was started for all patients when they were transferred to the Post-anesthesia Care Unit (PACU). Venous blood samples were collected for measuring the plasma norepinephrine (NE) 20 min prior to the induction of anesthesia (T₁), at the time of suturing (T₂), immediately post-extubation (T₃), 5 min post-extubation(T₄) and 30 min post-extubation (T₅). The Ramsay scores at T₄, T₅ and 60 min post-extubation and degree of emergence agitation were recorded.Resting visual analogue score (VAS) at postoperative 1 h (T₇), 4 h (T₈), 12 h (T₉), and 24 h (T₁₀), and frequency of PCIA button pressing and consumption of analgesics during postoperative 24 hours were also recorded. The postoperative adverse reactions were observed for all the patients. SPSS statistics 21.0 was used for data analysis. Results The plasma NE was significantly decreased in DD group than DEX group and DEZ group from T₂ to T₅ (P<0.05). Ramsay scores at T₄-T₆ were significantly higher and the emergence agitation during recovery period significantly lower in DD group than DEX group and DEZ group (P<0.05). VAS at T₇-T₁₀, frequency of PCIA button pressing and consumption of analgesics during postoperative 24 hours were significantly lower in DD group than DEX group and DEZ group (P<0.05). The incidences of hypertension, nausea and vomiting were significantly lower in DD group than DEX group and DEZ group (P<0.05). Conclusion Dexmedetomidine in combination with dezocine exerts satisfactory prophylactic analgesic effects in the hypertensive elderly patients undergoing thoracoscopic surgery, relieving the stress reaction, decreasing the emergence agitation and reducing the postoperative pain.