Abstract：In the Yarlung Zangbo Great Canyon area, endemic and massive diseases of skeletal growth and development seriously affect the health of the residents and economic and social development. China Geology Survey has carried out regional geochemical survey of the Bomi and Mêdog sheets in the interior of the Yarlung Zangbo Great Canyon. The results indicate the following environmental geochemical characteristics: the vital elements Fe, P, Ca, Mg, Mn, Co and Zn are lower than their average values of stream sediments in China; the elements Cu, Mo, Cr, V and Ni are much lower. Toxicity elements Ba, Be, Sr, Li are on the high side. U Th are much higher; the poisonous elements Ba, Be, Sr and Li are higher; U and Th are Sr/CaO and Ba/CaO are disproportional. The occurrence of endemic diseases is closely related to the inferior environmental geochemical quality. Research also shows that large-scale material exchange and special geochemical landscapes resulting from plate movement in the great canyon area are the deep-seated causes for the inferior quality of the geochemical environment and occurrence of endemic diseases in the Yarlung Zangbo Great Canyon.noticeably higher and P/F,