Objective To observe the effects of comprehensive measures of changing grain,selenium supplementation,off-site education and resettlement on prevention of children's Kashin-Beck disease in Aba state.Methods Fifty eight villages in Aba Kashin-Beck disease areas were chosen as intervention points in Aba state Sichuan province from 2007 to 2011.Based on the implementation of prevention and control measures,the villages were divided into off-site education + changing grain + selenium supplementation group and resettlement + off-site education + changing grain + selenium supplementation group,Geletuo town of Seda county,Ganzi state was selected as a control point,and right-hand anteroposterior X-ray examination(including the wrist) was carried out on children aged 6-13 from 2007 to 2011 annually.Clinical and X-ray diagnosis of Kashin-Beck disease was made in accordance with "the Diagnostic Criteria of Kaschin-Beck Disease"(GB 16003-1995).The effects of prevention and control measures were evaluated by comparing the child X-ray detection rate before and after the implementation of the measures.Results The average X-ray positive detectable rate of children in the intervention points was 2.07％(66/3181),2.72％ (69/2540),1.16％ (35/3017),0.56％ (19/3397) and 0.56％ (24/4273),respectively from 2007 to 2011,with a downward trend (x2trend =66.74,P ＜ 0.01).There was a downward trend in the average X-ray positive detectable rate of children in off-site education + changing grain + selenium supplementation group [1.60％(29/1809),2.63％ (39/1484),1.29％ (25/1941),0.64％ (15/2332),0.42％ (10/2379)] and resettlement + off-site education + changing grain + selenium supplementation group [2.70％ (37/1372),2.84％ (30/1056),0.93％(10/1076),0.38％ (4/1065),0.74％(14/1894)] (x2trend=30.97,35.19,all P ＜ 0.01).The average X-ray positive detectable rate of children in the intervention group was 0 from 2007 to 2010,and was 1.61％ (1/62) in 2011.The difference of X-ray positive detectable rate was not statistically significant in the control group in the 5 years from 2007 to 2011.The difference of children's X-ray positive detectable rate was not statistically significant between control group and intervention group.Conclusions The effect of taking changing grain,selenium supplementation,off-site education and resettlement comprehensive measures to prevent children's Kashin-Beck disease is not significant in those places where the state of Kaschin-Beck disease is not active.