Ｏｂｊｅｃｔｉｖｅ　To systematically review the safety and clinical efficacy of dexmedetomidine(Dex) combined with local anesthetics in brachial plexus block.　Methods　The relevant randomized controlled trial(RCT) were searched in Cochrane Library, PubMed, Embase, CBM, CNKI, WanFang Data and VIP databases(updated to July 2016). After the data was extracted and the quality was assessed in accordance with the inclusion and exclusion criteria, the Meta-analysis was conducted with RevMan5.3 software.　Results　A total of 13 RCT involving 809 patients were enrolled. The results of Meta-analyses showed that compared with local anesthetics alone, dexmedetomidine combined with local anesthetics can reduce the onset time of sensory block[mean difference(MD)=-1.87, 95%CI=(-2.85, -0.90), P<0.01], motor block[MD=-2.15, 95%CI=(-3.16, -1.14), P<0.01] and prolong the duration of sensory block[MD=219.57, 95%CI=(113.85, 325.29), P<0.01], motor block[MD=187.34, 95%CI=(83.65, 291.03), P<0.01]. Duration of analgesia was longer in the group which combined with Dex[MD=217.76, 95%CI=(94.04, 341.47), P<0.01], and it increased the intra-operative incidence of bradycardia[odds ratio(OR)=10.69, 95%CI=(4.37, 26.12), P<0.01], but showed no difference in low blood pressure[OR=3.23, 95%CI=(0.84, 12.45), P=0.09].　Conclusions　Dex combined with local anesthetics is superior to local anesthetics alone in the onset time of nerve block and prolongation of the duration of brachial plexus block. But drug combination increases the occurrence of bradycardia during operation.