Objective To investigate the effect of the application of tranexamic acid in unilateral total knee arthroplasty (TKA)with different methods .Methods Totally 120 cases of primary unilateral TKA patients admitted from June 2013 to May 2012 were studied ,including 33 males and 97 females ,with the average age of (65 ± 9) years (31 to 81 years) .Patients were divided into intravenous tranexamic acid group (group V ) ,topical tranexamic acid group (group T ) and irrigation using tranexamic acid group (group I) ,and control group (group C) .There were 30 cases in each group .Four groups of patients had no differences in age ,gender ,body mass index and disease diagnosis ,operative time ,preoperative hemoglobin ,preoperative hematocrit differences sta‐tistically(P>0 .05) .Postoperative blood loss and blood transfusion were observed .Groups were compared using one‐way ANOVA analysis .Results The total blood loss of group V was (368 ± 95)mL ,total blood loss of group T was (407 ± 118)mL ,both were less than the control group (509 ± 96)mL ,the difference was statistically significant (P<0 .05) .The differences between the blood loss of group I (491 ± 122) mL and the control group was not statistically significant (P=0 .924) .Group V showed the least a‐mount of hidden blood loss .Group T showed the least amount of visible blood loss .There were not deep vein thrombosis ,infections and other complications in any groups .Conclusion Intravenous and topical application of tranexamic acid can significantly reduce postoperative blood loss in TKA .Irrigation with tranexamic acid can not reduce the blood loss effectively .