Abstract: Objective To evaluate the effect of intra-articular application of tranexamic acid (TXA) on reducing blood loss after total knee arthroplasty (TKA). Methods One hundred and twenty patients who had undergone unilateral TKA in Inner Mongolia Provincial Crops Hospital of PAPF from May 2012 to December 2014 were randomly divided into two groups.Patients in TXA group (n=60) were administered 2 g of tranexamic acid in 80 ml normal saline into articular cavity after closure of the joint capsule, while those in control group were administered 80 ml of normal saline.The drainage tube of patients in both groups were clamped for 2 h.The perioperative total blood loss, dominant blood loss after operation, hidden blood loss, total blood transfusion, transfusion rate, thrombus related events were recorded. Results The perioperative total blood loss, dominant blood loss after operation, hidden blood loss, total blood transfusion, transfusion rate, maximum loss of hemoglobin of group TXA were significantly less than those of control group (709.4±77.5)ml vs (1 311.7±204.4) ml, (301.2±82.5) ml vs (683.5±105.1) ml, (400.7±291.3) ml vs (806.8±75.9) ml, (235.3±35.5) ml vs (682.4±124.5) ml, 26.67% vs 70.00%, (2.51±0.98) g/dl vs (3.66±1.19) g/dl, P< 0.05.Hemoglobin in 1 d, 3 d, 14 d after operation of group TXA were significantly higher than control group (10.12±1.11) g/dl vs (8.81±1.30) g/dl, (11.33±1.52) g/dl vs (10.14±1.23) g/dl, (11.52±1.03) g/dl vs (10.61±1.32) g/dl, P< 0.05.There were no significant differences in FIB, PT, APTT at 3 hours after operation between two groups (P> 0.05).No thrombus related event was found in both two groups. Conclusion Tranexamic acid is effective and safety in reducing the postoperative blood loss by intra-articular application after TKA.