In order to provide the evidence for the application of DYS413(YCAIII) locus in forensic medicine and population genetics by investigating its polymorphism in the Mongolians lived in the Inner Mongolia Autonomous Region, China, to collect 120 unrelated male Mongolians' venous blood, who lived in the Inner Mongolia Autonomous Region, and the blood is anticoagulant with EDTA, then to extract DNA by using the method of phenol-chloroform and amplify the DYS413 locus with PCR. The products were separated with 6% non-denatured polyacrylamide/bisacrylamide gels(19:1) electrophoresis and stained with 1 per thousand nitrate of silver(AgNO(3)). There are total 30 different haplotypes in Mongolians, the frequencies are from 0.0007 to 0.01361, the HD(haplotype diversity) is 0.94054. It shows that DYS413 locus is high valuable in the application of forensic medicine and population genetics.