Aim To explore frequency of angiotensin converting enzyme (ACE) gene insertion/deletion( I/D ) polymorphism and effect of ACE gene polymorphism on level of serum ACE and blood lipid in patient with essential hypertension and healthy subjects. Methods 216 subjects (98 heathy subjects and 118 hypertensives) were collected for the determination of the I/D genotype in intron 16 of ACE gene by polymerase chain reaction(PCR) and the level of serum ACE, total cholesterol (TC), triglycerides(TG), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol (HDLC), lipoprotein (a) [ Lp( a) ] , apolipoprotein AI (ApoAI), apolipoprotein B (ApoB). Results The frequency of I/D genotypes and D and I alleles of the ACE gene had no significant difference between hypertensives and healthy subjects (X2 = 0.468, P = 0.791; X2 = 0. 379, P = 0.538, respectively) . The level of serum ACE activity in deletion homozygotes (genotype DD) was the highest among three genotypes, and the lowest in insertion homozygotes (genotype II ), and intermediate in heterozygotes( genotype ID) (F= 17. 107, P = 0.000). Hypertensives had significantly higher TC, LDLC, Lp(a) than those of control group (p<0.0l). The level of blood lipid was significantly different among genotype DD, genotype ID, and genotype II in hypertensives group ( P< 0. 01). The level of TC, LDLC, HDLC, ApoB was significantly different among three genotypes in control group ( P< 0.05).Conclusions ACE gene polymorphism is associated with level of serum ACE and blood lipid. The level of serum ACE and blood lipid is higher in genotype DD than in genotype ID and genotype II .