Objective To evaluate the efficacy and safety of botulinum toxin A in the prophylactic treatment of migraine.Methods PubMed, Embase, Cochrane Library, SinoMed (CMB), CNKI, and Wanfang Data were searched for relevant randomized controlled trials(RCTs),and Review Manager 5.3 software was used to perform a meta-analysis.Results A total of 12 RCTs were included, with 4131 patients in total. The meta-analysis showed that there was no significant difference in the reduction in monthly average frequency of migraine attacks between the experimental group and the placebo group (mean difference[MD]=-0.1, 95% confidence interval[CI]:-0.41 to 0.21, P=0.53). The subgroup analysis based on the type of migraine showed that for patients in the chronic migraine subgroup, the botulinum toxin A group had a significantly greater reduction in monthly average frequency of migraine attacks compared with the placebo group (MD=-0.43, 95%CI:-0.70 to -0.17, P=0.001), while for patients in the episodic migraine subgroup, there was no significant difference in the reduction in monthly average frequency of migraine attacks between the botulinum toxin A group and the placebo group (MD=0.08, 95%CI:-0.16 to 0.33, P=0.51). Compared with the placebo group, the botulinum toxin A group had significantly greater improvements in monthly average number of days with migraine attacks, monthly average number of days of medication for acute headache, and quality-of-life score (P<0.05). The botulinum toxin A group had a significantly higher overall incidence rate of adverse events than the placebo group (odds ratio[OR]=1.38, 95%CI:1.20 to 1.58, P<0.00 001), but no serious adverse events were observed.Conclusions Botulinum toxin A can effectively reduce monthly frequency of migraine attacks, number of days with migraine, and number of days of medication for acute headache and improve quality of life in patients with chronic migraine, with a lack of marked effect on episodic migraine, and the adverse eventsare tolerable.