Background: The Tibetan group is one of the oldest Sino-Tibetan ethnic groups. The origin, migration as well as the genetic background of Tibetans have become the research hotspots in the field of forensic genetics. The use of ancestry informative markers (AIMs) allows the investigation of the genetic background of the Gannan Tibetan group. Methods: In this study, the 165 ancestry informative single nucleotide polymorphism (AI-SNP) loci included in the Precision ID Ancestry Panel were used to genotype 101 Gannan Tibetans using the Ion S5 XL system. The forensic statistical parameters of 165 AI-SNP in the Gannan Tibetan group were calculated. Population genetic analyses including Nei’s genetic distances, phylogenetic analyses, pairwise fixation index, principal component analyses and population ancestry composition analyses were also conducted to evaluate the genetic relationships between the Gannan Tibetan group and other reference populations. Results: Forensic parameters of the 165 AI-SNP loci indicated that not all of the SNPs showed high genetic polymorphisms in the Gannan Tibetan group. Population genetic analyses indicated that the Gannan Tibetan group had close genetic affinities with East Asian populations, especially with the groups residing in its neighboring geographical regions. Conclusions: The 165 AI-SNP loci in the Precision ID Ancestry Panel showed high ancestral prediction powers for different continental populations. When trying to predict the ancestral information of East Asian subpopulations using this panel, the prediction results are not particularly accurate. The 165 AI-SNP loci showed varying degrees of genetic polymorphisms in the Gannan Tibetan group, and the combined use of these loci could be an effective tool in the forensic individual identification and parentage testing of this group. The Gannan Tibetan group has close genetic affinities with East Asian populations compared with other reference populations, especially tighter genetic relationships with the groups residing in its neighboring geographical regions.