Senile cataract has become the leading cause of visual impairment and even blindness in the world, but there are few reports on its relationship with methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms. This study is aimed to investigate the correlation between MTHFR gene polymorphisms or its enzyme metabolites and senile cataract. From January 2019 to June 2020, 663 patients with senile cataract at the Mianyang Central Hospital were enrolled as the observation group, and 646 healthy subjects were randomly selected as the control group. MTHFR gene polymorphisms (i.e., CC, CT, or TT genotypes) and serum homocysteine (HCY), folic acid (FOL), vitamin B (VitB), and vitamin B (VitB) levels were detected. The mutation rate of MTHFR C677T and HCY levels in the observation group were significantly higher than those in the control group, whereas FOL, VitB, and VitB were significantly lower. With an increase in the MTHFR C677T mutation, HCY showed an upward trend, whereas FOL and VitB showed a decreasing trend in both the observation and control groups. Multiple logistic regression analysis showed that HCY and FOL were associated with senile cataract and MTHFR mutations; VitB was only associated with senile cataract. Compared to that with the CC genotype, CT and TT genotypes were associated with an increased senile cataract risk. Monitoring MTHFR gene polymorphisms and changes in serum HCY, FOL, and VitB levels could provide references in predicting senile cataract.