Abstract： Objective To investigate the present prevalence state of children's Kaschin-Beck disease (KBD) in Xinghai county of Qinghai province,a relative active KBD area in 2009,and to investigate their nutritional selenium level of local children and the T-2 toxin contamination level in their staple food.Methods Right hand X-ray photographs of children aged 7 - 12 in Shang,Zhong and Xia villages of Tangnaihai countryside in Xinghai county were taken.X-ray diagnosis was carried out according to the "Diagnostic Criteria of Kashin Beck Disease" (GB 16003-1995 ).Selected samples (children's hair,drinking water and their staple food) were collected according to X-ray film taken.Selenium contents in hair,drinking water and staple food samples were measured by 2,3-diaminonaphthalene fluorescence,and T-2 toxin in staple food sample was detected with enzyme-linked immunosorbent assay(ELISA) kits.Results Total X-ray detection rate of children KBD was 12.20％(31/254) and KBD positive rate of children in Xia village was up to 14.97％(22/147),Shang village was up to 9.52％(6/63),and Zhong village was up to 6.82％ (3/44).The selenium level in children's body and outer environment was very low,namely,the selenium content in hair,drinking water,wheat and flour was (0.250 ± 0.136)mg/kg,(0.156 ± 0.046)μg/L,(0.0045 ± 0.0030)mg/kg,and (0.0067 ± 0.0116)mg/kg,respectively.The T-2 toxin level was relatively high in children's staple food,which was (78.91 ± 46.17)μg/kg in wheat and (47.47 ± 46.47)μg/kg in flour.Conclusions In relative active KBD areas of Xinghai county of Qinghai province,the children's selenium nutritional level is low,and the T-2 toxin contamination level in their staple food is relatively high,which is consistent with the distribution of local children's KBD.