【Abstract】Objective To investigate the relationship between methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene polymorphisms and adverse pregnancy outcome. Methods From June 2016 to June 2018, 88 pregnant women with a history of adverse pregnancy in our hospital were selected as the study objects (adverse pregnancy group), and adverse pregnancy outcomes included intrauterine growth restriction (IUGR), intrauterine fetal death, fetal malformation and premature infants. In addition, 95 pregnant women with normal prenatal examination results and no adverse pregnancy outcome were selected as the control group. Taqman MGB technique was used to detect the distribution frequencies of C677T locus of MTHFR gene and A66G locus of MTRR gene in plasma; and the relationships between polymorphisms of C677T locus of MTHFR gene and A66G locus of MTRR gene and adverse pregnancy outcome were analyzed. In addition, the influencing factors of adverse pregnancy outcome were analyzed by Logistic regression. Results There were wild CC type, heterozygous CT type and homozygous TT type in C677T locus of MTHFR gene and there were wild AA type, heterozygous AG type and homozygous GG type in A66G locus of MTRR gene. Compared with those in the control group, the frequencies of CT, TT genotypes and T allele at C677T locus of MTHFR gene in the adverse pregnancy group were significantly higher (P＜0.05). The frequencies of AG, GG and G allele at A66G locus of MTRR gene were significantly higher (P＜0.05). The incidences of IUGR, intrauterine fetal death, fetal malformation and preterm infants in patients with wild CC type, heterozygous CT type and homozygous TT type at C677T locus of MTHFR gene, wild AA type, heterozygous AG type and homozygous GG type at A66G locus of MTRR gene in the three groups increased in turn, and the difference among the three groups was statistically significant (P＜0.05). Heterozygous CT type and homozygous TT type at C677T locus of MTHFR gene, heterozygous AG type and homozygous GG type at A66G locus of MTRR gene were the risk factors of adverse pregnancy outcome (P＜0.05). onclusion MTHFR and MTRR gene polymorphisms in plasma are closely related to the occurrence of adverse pregnancy outcomes, which may be used as an indicator to predict adverse pregnancy outcomes.