Abstract: Objective　To explore the correlation between 5,10- methylenetetrahydrofolate reductase (MTHFR) gene polymorphism (C677T) and tetralogy of Fallot in children. Method　PubMed, China National Knowledge Infrastructure, Wanfang and VIP databases were searched. A comparative study of MTHFR gene polymorphism (C677T) and tetralogy of Fallot in children published before July 2017 were collected. According to the inclusion and exclusion criteria, the documents which did not meet the requirements were excluded. After having Hardy-Weinberg genetic balance test, meta-analysis was performed and sequential test analysis (TSA) was used to test the results. Results　A total of 7 articles were included, including 1222 cases of tetralogy of Fallot and 1443 of controls. The results of meta analysis showed that the total OR value of the MTHFR gene polymorphism (C677T) allele model (T to C) was 1.63 with 95% CI of 1.41~1.88. The total OR value of the dominant gene model (TT+TC to CC) was 1.67 with 95% CI of 1.34~2.10. The total OR value of the recessive gene model (TT to TC+CC) was 2.08 with 95% CI of 1.64~2.63. The total OR value of the co-dominant heterozygote gene model (TC to CC) was 1.36 with 95% CI of 1.07~1.74. The total OR value of the co-dominant homozygote gene model (TT to CC) was 2.56 with 95% CI of 1.92~3.41. Conclusion　The MTHFR C677T gene polymorphic loci can increase the risk of tetralogy of Fallot.