本文对18种石斛属药用植物及其混伪品的叶绿体psbK-psbI序列进行PCR扩增和测序,比较分析其序列特征。石斛属药用植物叶绿体psbK-psbI基因间隔区长度为474~513 bp,GC含量25.4%~27.6%,变异位点71个,简约信息位点46个。石斛属种间K2P遗传距离为0.006 1~0.058 1,平均为0.028 4,与混伪品密花石豆兰之间K2P遗传距离为0.093 2~0.120 4。石斛属种间均能在NJ树中明显区分,6份待检样品均成功鉴定。叶绿体psbK-psbI序列可作为石斛属物种分子鉴定的候选标记。 In this paper, 18 species of Dendrobium medicinal plants and their adulterants chloroplast psbK-psbI sequence PCR amplification and sequencing, comparative analysis of its sequence characteristics. The length of chloroplast psbK-psbI gene from Dendrobium is 474-513 bp in length, with a GC content of 25.4% -27.6%, 71 mutated sites and 46 parsimony informative sites. The genetic distance of K2P between Dendrobium species was 0.006 1 ~ 0.058 1, with an average of 0.028 4. The genetic distance to K2P of Daphne camellia was 0.093 2 ~ 0.120 4. Dendrobium species can clearly distinguish between NJ trees, 6 samples were successfully identified. The chloroplast psbK-psbI sequence can be used as a candidate marker for molecular identification of Dendrobium species.