Objective:To investigate the genetic polymorphism of 19 X-STRs loci in the Beichuan Qiang and Xichang Yi ethnic groups in Sichuan Province,evaluate their forensic application value,and analyze their population structure.Methods:Dry blood spot samples were collected from 246 unrelated individuals(188 males and 58 females)of the Beichuan Qiang ethnic group and 281 unrelated individuals(116 males and 165 females)of the Xichang Yi ethnic group.The dry blood spot samples were directly amplified using the MicroreaderTM19X ID System kit,and the PCR products were subjected to capillary electro-phoresis using an ABI3500 genetic analyzer,GeneMapper?ID-X software automatically classifies.Results:A total of 150 alleles were detected in the Beichuan Qiang ethnic group,with a frequency range of 0.003 3～0.828 9.In the Xichang Yi ethnic group,a total of 164 alleles were detected,with a frequency range of 0.002 2～0.800 4.After statistical testing,the gene frequency dis-tribution of the two ethnic minority groups conform to Hardy Weinberg equilibrium law(P>0.05),and after Bonferroni correc-tion,there were no loci with linkage disequilibrium.In the Beichuan Qiang ethnic group,the combined discrimination power for males(PDM)and combined discrimination power for females(PDF)were 0.999 999 999 945 624 and 0.999 999 999 999 999 993 22,re-spectively.The combined mean exclusion chance in duos(MECD)and mean exclusion chance in trios(MECT)were 0.999 999 591 813 975 and 0.999 999 999 465 296,respectively.In the Yi ethnic group of Xichang,the combined discrimination power for males(PDM)and combined discrimination power for females(PDF)were 0.999 999 999 873 529 and 1,respectively.The combined mean exclusion chance in duos(MECD)and mean exclusion chance in trios(MECT)were 0.999 999 284 224 924 and 0.999 999 998 931 424,respec-tively.Conclusion:The MicroreaderTM19X ID fluorescence detection kit has a high overall polymorphism and good discriminatory ability in the Beichuan Qiang and Xichang Yi populations,and can serve as a powerful supplement and verification method for parental relation-ships and individual identification.