Objectives Placental abruption is an important risk factor for postpartum hemorrhage. This investigation aimed to study whether there were different changing patterns of hemostatic function during pregnancy between the uncomplicated women and pregnant women with placental abruption. Besides, we also focus on the value of hemostatic function tests for prediction of postpartum hemorrhage. Methods We involved pregnant women diagnosed with placental abruption who delivered at Peking University Third Hospital during December 1st, 2013 to December 1st, 2018. Non-pregnant women were also involved in our study and matched with women with placetnal abruption according to age and gestational age. Medical record, pregnancy outcomes and complete set of hemostatic test results were also collected. Results Our research involved an overall of 152 pregnant women diagnosed with placental abruption and 268 uncomplicated women. Among pregnant women with placental abruption, PT[10.00(9.89-10.10) vs 9.86(9.81-9.92), P=0.023], APTT [28.52(28.01-29.03) vs 27.10(26.84-27.35), P<0.001] and TT [13.45(13.24-13.67) vs 12.88(12.78-12.97), P<0.001] grew significantly higher than the uncomplicated group during the third trimester while fibrinogen level of women with placental abruption [4.11 (3.94-4.28) vs 4.35 (4.28-4.43), P=0.011] was lower than the uncomplicated women at the time of delivery.. Levels of FDP and D-dimer rose throughout gestation but showed no significant difference between women with placental abruption and the uncomplicated women. Only PT[ (10.2±1.3) vs (9.65±0.53), P=0.020] and FIB [(3.41±1.29) vs (4.30±0.94), P=0.001] showed significant difference between the two groups at the time of delivery. The receiver operating characteristic curve showed that the area under the curve of PT was 0.632 (0.517-0.748) in predicting postpartum hemorrhage while AUC of FIB was 0.703 ( 0.596-0.810). Conclusions Different changing pattern of hemostatic system exists between pregant women with placental abruption and uncomplicated women. Levels of FIB and PT at the time of delivery had predictive value in predicting postpartum hemorrhage.