Name and Origin of Xueyantuo Tribe

Many scholars made textual research about name and territory of Xueyantuo tribe,but conclusions were either errors or inconsequence.There was a key stone about derivation of Xueyantuo tribe in Tong Dian written by Du You.According to viewpoint of Du You,one embranchment of Xueyantuo tribe is called Yan Tuo and descendant of He Lan tribe.And this viewpoint was approved by non-Chinese history materials.We know territory of Xueyantuo tribe easily,after understanding derivation of Xueyantuo tribe.After researching,we can know that original territory of Xueyantuo tribe should be in north-desert region.