Objective To evaluate the influence of dexmedetomidine on the stress of elderly patients with cardiovascular risk undergoing gastrointestinal laparoscopic surgery. Methods From August 2014 to December 2015, 210 patients undergoing elective laparoscopic gastrointestinal operations were randomly divided into three groups, including the low concentration group (group D1), the high concentration group (group D2), and the control group (group C), with 70 cases in each group. The patients in group D1 and group D2 were injected with dexmedetomidine (0.4 and 0.8 μg/kg respectively) by infusion pump before anesthesia induction, and were continuously pumped with dexmedetomidine [0.4 and 0.8 μg/(kg·h) respectively] until the end of the surgery. Meanwhile, the patients in group C were injected with normal saline of the equal volumes. The heart rate and mean arterial pressure (MAP) was recorded before anesthesia, after endotracheal intubation and extubation. Myocardial ischemia and cardiovascular adverse events thatneeded to be handled were recorded. The concentrations of dopamine, adrenaline (AD) and noradrenaline (NE) were monitored at 15:00 one day before surgery (Ty), one hour after the beginning of surgery (T0), and at 15:00 of the 1st, 2nd, and 3rd day after surgery (T1, T2, T3). Results A total of 178 patients completed the study and were enrolled in this study, including 60 cases in group D1 and 59 cases in group D2 and C respectively. In group D1 and D2, the heart rates after intubation [(80.4±9.6), (68.2±10.5) times/minutes], extubation [(70.1±6.2), (69.7±7.8) times/minutes] and MAP after extubation [(100.2±12.0), (98.0±13.1) mm Hg (1 mm Hg=0.133 kPa)] were lower than those in group C [(98.4±10.5) and (95.2±7.3) times/minutes; (121.8±10.5) mm Hg], and the differences were significant (P<0.05). The bradycardia and hypotension in group D2 (27.12%, 22.03%) was significantly higher than those in group C (3.39%, 8.47%). Hypertension in group D1 and D2 (5.00%, 1.69%) was significantly lower than that in group C (37.29%), and the differences were significant (P<0.05). Compared with the base value at Ty in the three groups, the concentration of dopamine at T0-T3 in group C, at T0-T1 in group D1, and at T0 in group D2 increased significantly (P<0.05); the AD at T0-T3 in group C, at T0-T2 in group D1, and at T0-T1 in group D2 increased significantly (P<0.05); the NE at T0-T2 in group C, and at T1 in group D1 increased significantly (P<0.05). Compared with group C at the same time, the DA at T3 in group D1 and at T1-T3 in group D2, the AD at T2-T3 in group D1 and at T0-T3 in group D2, the NE at T0-T1 in group D1 and T0-T3 in group D2, decreased significantly (P<0.05). Conclusions Dexmedetomidine can effectively restrain the changes of hemodynamics and catecholamine induced by perioperative stress responses in a dose-dependent manner. During the surgery of elderly patients with cardiovascular risk, the concentration of dexmedetomidine should be controlled moderately to gain the optimal effect.