Abstract: Objective To investigate the correlation between methylenterahydrofolate reductase (MTHFR) gene C677T polymorphism, homocysteine (Hcy), folate and coronary heart disease (CHD) in the Han population of Ningxia, China. Methods In this case-control study, we selected 202 patients with CHD and 199 normal controls in Han population from Ningxia. The gene polymorphism of MTHFR C677T was detected by PCR-RFLP assay. Plasma Hcy concentrations were measured by fluorescence polarization immunoassay (FPIA) and serum folate and vitamin B12 concentrations by chemiluminescent immuno assay (CLIA). Results (1) In CHD and control groups, the frequencies of MTHFR C677T genotype were CC (homozygous wild) 23.3% vs 20.7% , CT (heterozygous) 52.3% vs 54.5% and TT (homozygous mutant) 24.4% vs 24.8% respectively. There was no difference in the genotype and allele frequency distribution of MTHFR C677T polymorphism between two groups. (2) In CHD group, the plasma Hcy concentration of individuals with CC genotype was lower than that of T allele carriers (10.84 μmol/L vs 12.24 μmol/L, P< 0.01). The plasma folate concentration of individuals with CC genotype was higher than that of T allele carriers (5.38 μg/L vs 3.72 μg/L, P=0.01). Conclusion There was no significant difference between CHD patients and normal people in genetic polymorphism of MTHFR C677T in Han population of Ningxia. The polymorphism of MTHFR C677T was related to the level of plasma Hcy and folate, which possibly were the risk factor of CHD.