To study the distribution of Eco31I restriction polymorphism in nucleotide -204 of 7alpha-hydroxylase gene(CYP7A1)in Sichuan Han population of China and association of the polymorphism with coronary heart disease(CHD),CYP7A1 genotyping was performed by using PCR-RFLP approach in 183 CHD patients and 101 control subjects. 7alpha-hydroxylase gene allele frequencies of C,A were 0.840 and 0.160 in CHD group and 0.822 and 0.178 in control group,respectively. There was no significant difference in frequencies of allele and genotypes in A-204C polymorphism between CHD group and control group (P>0.05). However, in CHD patients there was significant difference in total cholesterol (TC) levels among CC,CA and AA genotypes (P<0.05) ,and the levels of high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) in CHD patients with AA genotype were lower than those in CHD patients with CC and CA genotypes(P<0.05). In control group there was significant difference in TC levels between CC and CA genotypes (P<0.05) . The frequencies of C,A alleles at A-204C polymorphic site were significantly different from those reported in white people(P<0.05). The results indicating that no direct association was found between the A-204C polymorphism and CHD,but there was significant correlation between this polymorphism and the levels of TC ,and there was significant correlation in CHD patient group between this polymorphism and levels of HDL-C and LDL-C.