Objective To investigate the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism and unexplained embryo arrest relationship.Methods By the method of gene chip analysis of MTHFR gene C677T polymorphism;select August 2014 and September 2015 in Zhoukou City Center Hospital infertility clinic unexplained Embryo arrest was more than or equal to 2 349 times pregnant women as the case group,and 421 without abortion history of health by women as the control group.The genotype and allele frequency distribution of embryo arrest and C677T MTHFR were compared between the experimental and control groups.Results MTHFR C677T genotype C/C in experimental and control groups were distributed with significant difference [P ＜ 0.001,x2 =70.484,OR =0.267,95％ CI (0.195 ～ 0.366)].Genotype C/T in experimental and control groups was distributed without significant difference [P =0.714,x2 =0.156,OR =1.06,95％ CI (0.795 ～ 1.412)].T/T genotype in experimental and control groups was distributed with significant difference [P ＜ 0.001,x2 =98.812,OR =7.961,95％ CI (5.055 ～ 12.537)].C allele in experimental and control groups was distributed with significant difference [P ＜0.001,x2 =13.287,OR =0.291,95％ CI (0.236 ～0.361)].Allele t in experimental and control group was distributed with significant difference [P ＜0.001,x2 =13.287,OR =3.431,95％ CI (2.772 ～4.246)].Conclusions Embryo arrest was not associated with C677T gene mutations in MTHFR gene,and the high expression of T/T gene might be a risk factor for women of childbearing age.