ObjectiveTo systematically review the efficacy and safety of different low-molecular-weight heparins (LMWHs) for prevention of thromboembolic events in patients with atrial fibrillation (AF).MethodsPubMed, The Cochrane Library, EMbase, CBM, CNKI, VIP and WanFang Data databases were electronically searched to collect randomized clinical trials (RCTs) on efficacy and safety of different low-molecular-weight heparins (LMWHs) in preventing thrombotic diseases in patients with atrial fibrillation from inception to March 2021. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies; then, meta-analysis was performed by using Stata 16.0 software.ResultsA total of 11 RCTs involving 7 400 patients who were treated with enoxaparin, dalteparin, or tinzaparin to prevent thromboembolic events were included. The results of network meta-analysis showed that: in patients with AF and perioperative AF patients, there were no statistical differences in the incidence of stroke, TIA, major bleeding, minor bleeding, and all-cause mortality caused by dalteparin, enoxaparin, and tinzaparin. Furthermore, the surface under the cumulative ranking area (SUCRA) showed that enoxaparin was superior for prevention of stroke and TIA than dalteparin and tinzaparin. As for major bleeding, minor bleeding, and all-cause death, dalteparin treatment was superior than enoxaparin.ConclusionsCurrent evidence showed enoxaparin to be a viable option for high ischemic risk AF patients requiring LWMH treatment, while dalteparin to be a viable option for those with bleeding high risk. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify the above conclusions.