Objective To investigate the influence of the genotype distribution of methylenetetrahydrofolate reductase (MTHFR) C677T,A1298C and methionine synthase reductase (MTRR) A66G in threatened abortion of Chinese Han gestationalage women in Sanya city,which involved in the folic acid biosynthetic pathway among.Methods One hundred and thirty-nine samples of case group and the same number of control group were recruited from Sanya region in Hainan Province.Genomic DNA was extracted from the mucosal epithelium of the subjects.The gene polyrnorphisms of MTHFR and MTRR were detected by Fluorescence quantitative PCR technology.The distribution frequencies of both case group and control group.were analyzed and compared,to investigate the effect of the gene polymorphisms on threatened abortion.Results Both the case group and the control group complied with Hardy-Weinberg law.The genotype frequency of MTHFR C677T,MTHFR A1298C and MTRR A66G were not significantly different.Conclusion This study suggests that the gene polymorphism which involved in folic metabolism was not significantly different from the group of threatened abortion and the control group,and whether the metabolism related genes are the risk factors of threatened abortion need to be further discussed.