Insertion/deletion (InDel) markers have been treated as a prospective and helpful aid in the fields of forensic human identifications and biogeography origin researches for the past few years. In this study, we analyzed genetic polymorphisms and forensic efficiencies of 35 InDels in a novel multiplex PCR-InDel panel in a Chinese Mongolian group. All these 35 InDel loci were observed to conform to Hardy–Weinberg equilibrium and linkage equilibrium. The mean values of expected heterozygosity and observed heterozygosity were 0.4788 and 0.4852, respectively. Besides, the interpopulation differentiations and genetic distributions based on 35 InDels found that the Chinese Mongolian group might have closer genetic relationships and similar population genetic structures with East Asian populations.