Abstract: ［Abstract］Objective To investigate the difference of MT4 G-201A of Metallothionein （metallotionein， MT） family gene locus single nucleotide polymorphisms （SNPs） in type 2 diabetes and essential hypertension. Mothods We selected 324 cases of patients with type 2 diabetes， 301 cases of patients with essential hypertension， 301 case of normal physical examination population. Polymerase chain reaction-restriction fragment length polymorphism（PCR-RFLP）analysis technology was used to detect MT4 G-201A polymorphism. Results （1） The genotype GG， GA and AA frequency of MT4 G-201A in 324 cases of patients with type 2 diabetes，301 cases of patients with essential hypertension，301 case of normal physical examination population were 39.5%，46.6%，13.9%；42.2%，48.5%，9.3%；and 42.5%，51.5%，6.0%， respectively. The genotypes in all the distribution were in Hardy-Weinberg equilibrium （P＞0.05）.（2） MT4 G-201A polymorphism: Three groups of genotype and allele frequency distribution （G and A） had differences （P＜0.05）; there was no difference between essential hypertension group and normal group （P＞0.05）；there was a difference between type 2 diabetes group and the normal group（P＜0.05）；there was no significant difference in genotype and allele frequency distribution（P＞0.05）.（3）MT4 G-201A polymorphism in Men: Three groups of genotype and allele frequency distribution had differences （P＜0.05）. In essential hypertension and type 2 diabetes group，there was no significant difference in genotype and allele frequency distribution（P＞0.05）.MT4 G-201A polymorphism between women:Three groups of genotype and allele frequency distribution had differences （P＜0.05），there was a difference between type 2 diabetes and normal group genotypes （P＜0.05）. Conclusions （1）There is correlation of MT gene G-210A polymorphism and type 2 diabetes， no association with essential hypertension. （2） There is a difference of MT gene G-210A polymorphism in type 2 diabetes in women， no difference in men.