Abstract: Objective To compare the efficacy of interscalene brachial plexus block using an ultrasound-guided method with neutostimulator-guided method. Methods：Ninety ASAⅠ~Ⅱ patients scheduled for surgery of the upper extremity were randomly allocated into three groups(n=30), Control group: nerve stimulator-guided and single-injection group; US group: ultrasound-guided with nerve stimulator confirmation and single-injection group; UD group : ultrasound-guided with nerve stimulator confirmation and double-injection group. 30ml 0.5% ropivocaine was injected in each group.The patient in group UD group received half the volume of ropivocaine injected around the two target nerves. Results The average onset time of sensory blockade in the UD group was significantly shorter than in the US group and Control group .The rate of satisfactory sensory blockade in the UD group was significantly higher than in the US group and Control group. Conclusions Ultrasound-guided interscalene brachial plexus block may shorten the onset time with fewer adverse events. The ultrasound-guided double-injection method may significantly improve the quality of blockade.