Abstract：The Kaschin-Beck disease is an endemic disease widespread in China. It prevails in the Aba Prefecture, Sichuan Province, and especially is seriously prevalent in the Bobso area, Zoigê. Through the study of the cause of the disease, characteristics of bioelements and element background values in the disease and non-disease areas by previous experts, the authors think that the cause of the Kaschin-Beck disease probably is due to the concentration of humic acid, lower values of Se, Mo, Cu and V and the lack of Ca resulting from antagonism of B, Sr and P on CaO. Meanwhile, through the element geochemical study of the soil and water in the "Pa" (lying on the ground) disease area in the 1:200 000 Neijiang Sheet, the authors think that the causes of the two diseases bear some similarities, which may corroborate the geochemical cause of such kind of endemic bone disease.