ObjectiveTo compare the functioning time, duration, cervical vascular blood flow and adverse effects of different concentrations of ropivacaine mesylate in performing stellate ganglion block (SGB) under Doppler ultrasound. MethodsA total of 240 patients (grade Ⅰ or Ⅱ classified by American Society of Anesthesiologists) aged between 23 and 62 years old ready to undergo SGB between January and April 2013 were chosen for our research. They were randomly divided into two groups with 120 patients in each. Group A and B received unilateral SGB with 7 mL of 0.239% and 0.596% ropivacaine mesylate respectively. Successful SGB was verified by Horner syndrome. The functioning time, duration, hemodynamic changes, cervical vascular blood flow and adverse effects were recorded and compared. ResultsHorner syndrome was observed in all patients. There was no significant difference in functioning time between the two groups (P>0.05). The duration of functioning was significantly longer in group B than that in group A (P<0.05). No significant difference was found in hemodynamic changes after SGB (P>0.05). No adverse effects were found in both groups. The blood flow of the vertebral artery and the internal carotid artery before the injection and 10 minutes after the injection were not significantly diferent (P>0.05). ConclusionSGB can be induced with 0.239% and 0.596% ropivacaine mesylate. We suggest using 0.596% ropivacaine mesylate by ultrasound-guiding because of the significantly longer functioning duration.