Objective：To evaluate the relationship between the polymorphism of MTHFR gene and the level of folic acid and homocysteine in the preconceptional women of Jiangsu Province. Methods: A total of 915 preconceptional women were recruited. The mutations of MTHFR rs1801131 and rs1801133 reported associated with congenital heart disease susceptibility were genotyped and the levels of homocysteine (HCY) and folic acid (FA) in peripheral blood were detected. Results：Among 915 women, the rate of homozygous mutation and heterozygous mutation of rs1801131 and rs1801133 were 3.39%, 28.74% and 20.55%, 48.20%, respectively. There were significant differences in the level of HCY and FA among rs1801133 CC, CT and TT genotypes. In TT group, HCY was higher than that of CC and CT group, but folic acid was lower than that of CC group. HCY level of compound mutant individuals rs1801131 AC and rs1801133TT was significantly higher than that of the individuals both with rs1801131AC and rs1801133CC or CT. Conclusion：It is found that there is a correlation between the concentration of FA and HCY in peripheral blood and the polymorphisms of MTHFR gene which is associated with congenital heart disease. Therefore, for preventing congenital heart disease that might emerge from the genetic polymorphisms, it is expected to help guidance of FA supplementation in preconceptional and early-pregnancy health care that understanding the mutations of MTHFR gene, and their correlation between the concentration of HCY and FA of preconceptional women.