Objective:The effect of tranexamic acid (TA) on patients receiving total knee arthroplasty (TKA) has been reported in many small clinical trials.But single trials are not sufficient enough to clarify the effectiveness and safety of TA.So,we carried out a meta-analysis of randomized controlled trials to investigate the efficacy and safety of the intravenous use of TA in TKA.Methods:Literatures were retrieved in Cochrane Library,OVID,PubMed,EMBASE,CNKI and Wanfang Data.All the related literatures were checked by two independent investigators and only the high quality randomized controlled trials were enrolled.Relevant data were analyzed using RevMan 5.1 to compare the difference of blood loss,transfusion and complications between TA group and control group.Results:There were 353 related literatures and only 22 randomized controlled trials met the inclusion criteria.The use of TA in TKA significantly reduced total blood loss by a mean of 435.41 ml (95％ CI300.62-570.21,P＜0.01),postoperative blood loss by a mean of 406.69 ml (95％ CI333.16-480.22,P＜0.01).TA also significantly lowered the transfusion rate (risk difference 0.30,95％ CI0.21-0.39,P＜0.01) and transfusion volume (mean difference 0.95 unit,95％ CI0.53-1.37,P＜0.01).The risks between TA group and control group in developing deep vein thrombosis and pulmonary embolism were not statistically significant.Conclusion:TA is beneficial for patients undergoing TKA,which can significantly reduce total blood loss,postoperative blood loss,transfusion rate,and transfusion volume.Meanwhile TA is recommended to reduce deep vein thrombosis and pulmonary embolism following TKA.