Objective To compare the resonance acoustic characteristics between 7~16 years old Down syn-drome children and normal children .Methods A total of 29 cases of 7~16 years old Down syndrome children and 90 cases of 7~16 years old normal children pronuanced /a/,/u/,/i/,each sound for 3 times ,every time 1 to 2 sec-onds .The oral resonance acoustic parameters ,including F1 (a) ,F2 (a) ,F1 (i) ,F2 (i) ,F1 (u) ,F2 (u) ,the distance of tongue and the distance of jaw ,were recorded by real analysis .Analysis of variance was used for the voice acous-tic .Results With age ,there was a significant decrease tendency of the value of F2 (a) and a very significant growth tendency of the values of F2 (i) and the distance of tongue in normal children .The value of F2 (i) inrcreased signifi-cantly in Down syndrome children .The values of every oral resonance acoustic parameters were not different signifi-cantly on sex in normal children .The values of F1 (i) and F1 (u) in Down syndrome boys were significantly less than those of in the Down syndrome girls ,but the the distance of jaw in Down syndrome boys were significantly greater than those of in the Down syndrome girls .The values of F2 (u) and F1 (i) in Down syndrome children were signifi-cantly greater than those of in normal children ,but the distance of tongue was significantly less than those of in nor-mal children .Conclusion With age ,in normal children ,the amplitude of the tongue forward movement and the range of tongue back and forward movement were increased significantly ,the oral focus moved forward gradually .In Down syndrome children ,the amplitude of the tongue back movement ,and the range of tongue back and forward movement ,were poor than those of in normal children .The Down syndrome children were easier to suffer from oral resonance disorder than normal children .