Abstract: Objective To understand the levels of serum homocysteine(Hcy) and its influencing factors in perinatal women in Qingzhen city,Guizhou province.Methods A total of 1421 healthy perinatal women were selected from the Maternal and Child Health Hospital of Qingzhen city from March to June 2019. According to the principle of informed consent,the serum Hcy concentration was detected by circulating enzyme method,and 5,10-was detected by real-time PCR. Methylenetetrahydrofolate reductase(MTHFR) C677 T locus polymorphism.Results ①The Hcy level in the <30 years old and ≥30 years old age groups were(6.20 ±2.30) and(5.94 ±2.13) μmol/L,respectively,and the difference was statistically significant between the two age groups(P<0.05). ②The serum Hcy levels before pregnancy,first trimester,second trimester,third trimester and postpartum were(7.14 ±1.56),(6.17 ±2.19),(5.72 ±2.28),(6.93 ±2.93) and(7.10 ±2.39) μmol/L,respectively,and the difference was statistically significant between different periods(P<0.05). ③According to the MTHFR C677T locus polymorphism,the serum Hcy levels of women with CC,CT and TT genotypes were(7.23 ±2.19),(7.60 ±2.20) and(9.02 ±2.53) μmol/L,respectively. The difference was statistically significant(P<0.05).Conclusion Serum Hcy levels in perinatal women are related to age,different periods of pregnancy and MTHFR C677T gene polymorphism. Monitoring Hcy level has important guiding significance for perinatal health care.