Background The use of tranexamic acid to prevent postpartum hemorrhage has often been controversial. Objectives To evaluate evidence from randomised controlled trials on the efficacy and safety of tranexamic acid in preventing postpartum hemorrhage. Search Strategy PubMed, EMbase and Cochrane Library, and Chinese database including CNKI, VIP and WanFang were searched. Selection Criteria Randomized controlled trials regarding tranexamic acid for the prevention of postpartum hemorrhage were included. Data collection and analysis Pooled relative risk was determined as the effect analysis statistic for binary variables, while pooled mean difference and standard mean difference was chosen for continuous variables. Results Preventive use of tranexamic acid was effective in reducing the incidence of postpartum hemorrhage in both cesarean section and vaginal delivery patients (RR=0.58, 95%CI 0.52-0.66, P＜0.00001), as well as reducing the volume of intrapartum blood loss ( -121.97, 95% CI-147.39, -96.55, P < 0.00001), and the need for blood transfusion (RR=0.36,95%CI 0.24-0.53,P＜0.00001) and additional medical measures to control bleeding (RR= 0.47, 95% CI 0.32-0.68, P <0.0001) following postpartum hemorrhage. Concerning safety, the medication was not found to increase the incidence of serious adverse reactions (RR=0.66, 95%CI 0.31-1.42, P=0.29) or thrombotic events (RR=1.14, 95%CI 0.39-3.35, P=0.61), but could increase the incidence of mild adverse reactions (RR = 1.55, 95% CI 1.13-2.13, P = 0.007). Conclusion Preventive use of tranexamic acid can reduce the incidence of postpartum hemorrhage in cesarean section and vaginal delivery, without increasing the incidence of postpartum thrombosis and other severe adverse events.