Studying　the　genetic　structure　of　each　ethnic　group　is　helpful　to　clarify　the　genetic　background　and　trace　back　to　the　ethnic　origin.　Tibetan　people　have　lived　in　the　Qinghai-Tibet　Plateau　(mean　elevation　over　4500　m)　for　generations,　and　have　well　adapted　to　the　high-altitude　environment.　Due　to　the　relatively　closed　geographical　environment,　Tibetans　have　preserved　their　representative　physical　characteristics　and　genetic　information,　thereby　become　an　important　research　group　in　human　genetics.　In　this　study,　genetic　characteristics　and　population　structures　of　two　Tibetan　groups　(Qinghai　Tibetans　and　Tibet　Tibetans)　were　revealed　by　35　insertion/deletion　polymorphism　(DIP)　loci,　aiming　to　provide　valuable　genetic　information　for　population　genetic　differentiation　analyses　and　forensic　identifications.　The　combined　discrimination　power,　cumulative　exclusion　probability　and　combined　match　probability　of　the　35　DIP　loci　in　Qinghai　Tibetan　and　Tibet　Tibetan　groups　were　0.9999999999999945,　0.9988,　5.56623　x　10(-15);　and　0.9999999999999904,　0.9990,　9.69071　x　10(-15),　respectively,　indicating　that　the　panel　possessed　a　strong　capability　for　Tibetan　personal　identifications.　Population　differentiations　and　genetic　relationship　analyses　among　the　two　studied　Tibetan　groups　and　other　27　comparison　populations　were　carried　out　using　the　Nei＇s　D-A　genetic　distances,　population　pairwise　genetic　distances　F-statistics　(F-ST),　analysis　of　molecular　variance　(AMOVA),　phylogenetic　tree　reconstruction,　principal　component　analysis　and　STRUCTURE　methods.　Results　demonstrated　that　the　most　intimate　genetic　relationships　existed　in　these　two　Tibetan　groups;　and　genetic　similarities　between　two　Tibetan　groups　and　the　populations　from　East　Asia　were　much　stronger　than　that　between　the　Tibetan　groups　and　other　geographical　populations.　Furthermore,　forensic　ancestral　informativeness　assessments　suggested　that　several　loci　could　be　regarded　as　ancestry　informative　markers　inferring　individual　biogeographic　origins　as　well　as　contributing　to　forensic　anthropology　and　population　genetic　researches.