This paper investigates the effect of music on the communication improvement of children with developmental disabilities. Forty subjects (18 boys and 22 girls) 7-12 years old, were divided into an experimental group (n = 20) which participated in music therapy activities and a control group (n = 20) which was discussing and watching television, both for one hour. The State-Trait Anxiety Inventory Scale for children was used to measure state and trait anxiety respectively. In addition, heart rate response to music therapy was monitored for assessing probable music therapy effect. Findings from paired t-tests revealed that the State Anxiety Inventory Scale score was significantly influenced by the music therapy (t = 5.36, p less than 0.001) as well as it was not significantly influenced by the discussing and watching television session (t = 1.02, p greater than 0.05: NS). Besides, heart rate alteration analysis revealed that music therapy helps calm young children with developmental disabilities. Consequently, music therapy could lead not only to significant improvements in young CWDD's psychological and physical well-being but also could produce mental benefits, and should constitute a part of therapeutically programs that aim both to the improvement of young CWDD's psychological state and quality of life. (Contains 3 tables and 3 figures.)