Abstract: AIM　To establish an allele specific PCR amplification (ASA-PCR) for determination of the genotype of CYP2D6*10B polymorphism in Chinese subjects. METHODS　CYP2D6*10B alleles of 65 healthy Chinese subjects were analyzed by a two-step PCR assay and the correlation of genotype and phenotype was studied. RESULTS　There were 20 CYP2D6*10B heterozygous genotypes subjects (wt/m) in 35 very extensive metabolizers (VEMs), which consisted the major part of VEM subjects (57%). Meanwhile, 20 subjects consisting 69% of 29 intermediate metabolizers were CYP2D6*10B homozygous mutant genotypes (m/m). The poor metabolizer was also m/m. The metabolic ratio of CYP2D6*10B m/m subjects were larger than wt/m and wild type, the values were -1.49±0.54, -2.20±0.49 and -2.47±0.61 (P<0.01). CONCLUSION　PCR-ASA was shown to be a rapid and specific method. It can be used to study the genetic polymorphism, especially CYP2D6 intermediate metabolism.