To study the relationship between angiotensin converting enzyme(ACE) gene polymorphism and angiotensin converting enzyme activity,the polymerase chain reaction(PCR) was used to detect an insertion/deletion(I/D) polymorphism of ACE gene in its sixteenth intron.The genotype,enzyme coupling spectrophotometry were used to measure serum ACE activity among the three genotypes.Results showed that the Serum ACE activities were (337 6?92 0),(292 7?76 5 )and(243 5?58 9)u/L for genotypes DD,ID and ⅠⅠ respectively.The findings indicate that the ACE gene polymorphism closely associated with serum ACE activity.