Abstract: OBJECTIVE To systematically review the efficacy and safety of new oral anticoagulants(NOACs) and warfarin in patients with atrial fibrillation aged<75 years and ≥ 75 years. METHODS Such databases as PubMed, Embase, the Cochrane Library, CNKI, Wanfang database, etc. were electronically searched for relevant studies from inception to June 2020. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by RevMan 5.3. RESULTS A total of 12 studies were included, including 7 randomized controlled trials(RCT) and 5 observational studies, including 572 968 patients. Meta-analysis results of <75 years old patients with atrial fibrillation showed that:①in RCT, compared with warfarin, NOACs could reduce the risk of stroke/systemic embolism(SSE), major bleeding, intracranial hemorrhage and all-cause mortality without reducing the risk of gastrointestinal bleeding; ②in observational studies, compared with warfarin, NOACs reduced the risk of stroke/SSE, major bleeding and intracranial hemorrhage with increasing the risk of gastrointestinal bleeding and all-cause mortality. Meta-analysis results of ≥ 75 years old patients with atrial fibrillation showed that:①in RCT, compared with warfarin, NOACs could reduce the risk of stroke/SSE and intracranial hemorrhage with increasing the risk of gastrointestinal bleeding, but without reducing the risk of major bleeding and all-cause mortality; ①in observational studies, compared with warfarin, NOACs reduced the risk of stroke/SSE, major bleeding, intracranial hemorrhage and all-cause mortality with increasing the risk of gastrointestinal bleeding. CONCLUSION For patients <75 years of age with atrial fibrillation, NOACs are more effective and safer than warfarin. For patients with atrial fibrillation ≥ 75 years of age, NOACs are superior to warfarin in stroke/SSE and intracranial hemorrhage, but inferior to warfarin in gastrointestinal bleeding. For the application of NOACs in elderly patients with atrial fibrillation, anticoagulant drugs need to be carefully selected according to specific conditions.