Objective To study the changes in the levels of prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), thrombin time (TT), D-dimer (DD), thrombin (AT) and fibrin (proto) degradation products (FDP), explore the influence of age factors on the levels of coagulation indicators in pregnant women, and establish PT, APTT, FIB, TT, DD, AT, FDP reference intervals in different pregnancy periods. Methods We selected 406 healthy pregnant women and 110 non-pregnant healthy controls. The pregnant women were divided into 152 cases in the first trimester group, 124 cases in the second trimester group, and 130 cases in the third trimester group. The relevant coagulation indexes of each group were detected and their level changes were analyzed. Analyze the influence of age on the coagulation function of each group of pregnant women. The non-parametric method was used to establish and verify the reference intervals of PT, APTT, FIB, TT, DD, AT, FDP of pregnant women in different pregnancy periods. Results There was no significant difference in coagulation index levels in the first trimester, the second trimester, and the third trimester in the two groups of age ＜30 years old and age ≥30 years old (P＞0.05). The PT level did not change significantly during the early, middle and late pregnancy (P＞0.05), and the reference interval was 10.20-11.90 s. The APTT level was not significantly different during the early and middle pregnancy (P＞0.05), the reference interval was 23.3-29.6 s, and the late reference interval was 22.8-29.4 s. The levels of FIB, TT, DD, AT, and FDP were significantly different during the early, middle and late pregnancy (P＜0.05). The reference intervals in the first trimester were 2.59~4.6 g/L, 13.3~16.1 s, 0.82 μg, respectively /mL, (73.3~101.9)%, 2.56 μg/mL, the reference intervals in the second trimester are: 2.59~5.1 g/L, 13~15.9 s, 0.95 μg/mL, (70.5~103.3)%, 4.4 μg /mL, the reference intervals in the third trimester are: 3.01~5.98 g/L, 13.3~15.7 s, 3.4 μg/mL, (73.4~113.6)%, 8.63 μg/mL.Conclusion The reference interval for routine coagulation indexes of pregnant women in different pregnancy periods has been preliminarily established to provide laboratory evidence for clinical diagnosis and prevention of maternal bleeding.