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目的:了解青海省自然疫源性病区小型兽类空间分布，并以线粒体细胞色素C氧化酶亚基I（COI）基因作为分子标记，对捕获的小型兽类进行分子水平的物种鉴定。方法:2009 - 2016年，在青海省6个州的16个市（县），采集小型兽类标本为研究对象，分析小型兽类地区分布、不同海拔分布、生态环境类型分布；采用PCR扩增小型兽类的COI基因部分片段序列（长度约650 bp），并进行同源性比较、遗传距离和系统发育分析。结果:共捕获小型兽类1 631只，分别隶属于3目7科21属30种；其中啮齿动物926只，分别隶属于5科19属25种，占56.78%。格尔木市采集的小型兽类数量最多（313只），2 800 ~ < 3 000 m的海拔段为小型兽类分布最高峰（532只），沙地草原捕获数量最多（612只）。共成功扩增292只小型兽类COI基因，同源性比对与目标序列一致。种内遗传距离为0.01% ~ 2.90%，种间遗传距离为4.00% ~ 12.00%，种间遗传距离大于种内遗传距离；属间遗传距离为13.00% ~ 21.00%，科间遗传距离为22.00% ~ 25.00%。邻接法（NJ）系统发育树显示，同种个体聚为有很高支持度的单一分支共形成20个，置信度为98% ~ 100%。结论:青海省小型兽类空间分布受地区、海拔、生态环境等自然地理因素的综合影响，且分子鉴定法可弥补形态学鉴定中的不足。“,”Objective:To understand the spatial distribution of small mammals in the areas of natural focus disease in Qinghai Province, and to identify captured small mammals at the molecular level using mitochondrial cytochrome C oxidase subunit I (COI) gene as molecular marker.Methods:In 2009 - 2016, the distribution of regional spatial, elevation distribution and ecological environment type of captured small mammals were analyzed in 16 cities (counties) of 6 prefectures in Qinghai Province. The partial COI gene fragment sequence (about 650 bp in length) was obtained by PCR amplification, which was further analyzed through homology comparison, genetic distance and phylogenetic analysis.Results:Totally 1 631 small mammals were captured that had belonged to 30 species of 21 genera, 7 families, 3 orders. Among them there were 926 rodent animals that had belonged to 25 species of 19 genera, 5 families, accounting for 56.78%. There was the largest number in Golmud (313 animals), the highest distribution of small mammals was found at the elevation of 2 800 - < 3 000 m (532 animals), the largest number of small mammals was found in the sandy grassland (612 animals). COI genes of 292 small mammals were successfully amplified, and the homology was consistent with the target sequence. The results showed that the intraspecific genetic distance ranged from 0.01% to 2.90%, interspecific genetic distance ranged from 4.00% to 12.00%, intergenus genetic distance was 13.00% - 21.00% and interfamily genetic distance was 22.00% - 25.00%. The interspecific genetic distance was significantly greater than the intraspecific genetic distance. Neighbor-Joining tree showed that the same species were clustered into a single branch with high support form a total of 20, with a confidence level of 98% to 100%.Conclusions:The spatial distribution of small mammals is influenced by geographical factors such as region, elevation and ecological environment in Qinghai Province. Molecular identification can make up for the shortcomings in morphological identification.