Objective To explore the effect and mechanism of preventing ankle instability through exer-cise, so as to provide evidence-based references for practice. Methods The randomized and controlled trials ( RCT) on preventing ankle instability through exercise published before December 2014 were searched for in the NCBI, CNKI, VIP and Wanfang databases by computer, supplemented by manual searching. Each study′s quality was evaluated according to the standards of the Cochrane handbook by 3 researchers. The outcome indexes were ex-tracted and analyzed using RevMan 5.2 software. Results After the initial selection, 665 papers (357 in English and 308 in Chinese) were retained. From these 92 were chosen after reading the titles and abstracts. Ultimately, 14 RCT studies ( 12 in English and 2 in Chinese) met the inclusion criteria. They showed that exercise improved ankle function and symptoms of ankle instability significantly [SMD=0.98, 95%CI (0.65,1.31), P≤0.01], improved muscle strength [SMD=1.50, 95%CI (0.99,2.01), P≤0.01], improved balance and postural stability [SMD=-0.54, 95%CI (-0.84,-0.25) ,P≤0.01] , but did not improve proprioception or neuromuscular functioning sig-nificantly. Conclusions Exercise can effectively improve muscle strength, balance and postural stability, but not proprioception or neuromuscular functioning. The details of these findings may be related to the exercise intervention chosen.