[目的]建立一步PCR法测定CYP2C19m2等位基因。[方法]根据等位基因特异扩增法（ASA）原理，设计两对分别对应于野生型基因和突变型基因的引物，经PCR扩增后进行基因分型。[结果]通过对60名随机健康受试者CYP2C19m2等位基因进行基因分型，发现其中49名为野生到纯合于，11名为CYP2C19m2杂合子，没有发现CYP2C19m2纯合子。[结论]ASA法可用于CYP2C19m2位基因分型，该法具有简便、快速、经济、可靠等优点。 [Objective] To establish a one-step PCR method for the determination of the CYP2C19m2 allele. [Method] According to the principle of allele specific amplification (ASA), two pairs of primers corresponding to wild-type and mutant genes were designed and genotyped by PCR amplification. [Results] CYP2C19m2 alleles were genotyped in 60 randomized healthy subjects, of which 49 were wild to homozygous and 11 were CYP2C19m2 heterozygotes, and no CYP2C19m2 homozygotes were found. [Conclusion] The ASA method can be used to genotype CYP2C19m2, which is simple, rapid, economical and reliable.