【目的】 粉蚧是一类以吸食植物汁液为生的半翅目昆虫，大多为农林生产的害虫。COⅠ基因是粉蚧分子系统学研究中较为常用的基因，根据不同的引物常分为2个区域：HCO-LCO region和region 2。为了促进粉蚧科的分类研究工作，探究这2个区域哪个在粉蚧物种分类中具有更高的准确性。【方法】 本研究从GenBank数据库中下载了粉蚧科中同时具有HCO-LCO region和region 2区域序列信息的共48种粉蚧的数据，计算遗传距离条形码间隙和鉴定准确率，并采用ML法分别构建系统发育树。【结果】 HCO-LCO region的准确鉴定率高于region 2；基于HCO-LCO region的粉蚧科遗传距离均随分类阶元的上升而增加，而region 2则出现了种间最大遗传距离大于属间最大遗传距离的现象；基于HCO-LCO region构建的系统发育树也更符合粉蚧的形态研究结果。【结论】 HCO-LCO region在物种识别鉴定方面优于region 2，能够更好的体现粉蚧科昆虫的系统发育关系，更适于粉蚧科的分类研究。

[Objectives]  To identify COⅠ sequence regions useful for resolving the taxonomy of the Pseudococcidae (mealybugs) and thereby improve understanding of the phylogenetic relationships within this family. Mealybugs are Hemipteran insects that feed on plant sap, and most are agricultural and forestry pests. The COⅠ gene is commonly used in molecular phylogeny and is often divided into two regions according to different primers; the HCO-LCO region and region 2. [Methods]  Sequence information on both the HCO-LCO region and region 2 from 48 Mealybugs was downloaded from the GenBank database. The genetic distance, barcode gap and BCM were calculated and a phylogenetic tree constructed using the ML method. [Results]  The rate of accurate species identification using the HCO-LCO region was higher than that using region 2. Genetic distances estimated based on HCO-LCO region variation increased with taxonomic level but those based on region 2 ranked the maximum genetic distance between species as greater than that between genera. A phylogenetic tree based on HCO-LCO region variation was more consistent with the morphological classification than one based on region 2. [Conclusion]  The HCO-LCO region was more useful than region 2 for species identification, and better reflects the developmental and evolutionary relationships among the Pseudococcidae than region 2.