Introduction: There is a strong correlation between muscle weakness and the mobility children with cerebral palsy. For this reason, the focus of the intervention programs has been changed to resistance exercises. The purpose of this study was effect of group resistance exercise with exciting music on spasticity, muscle strength and walking ability for children with cerebral palsy. Methods: This study had a quasi-experimental design with an experimental and control group. The study population consisted of all children with cerebral palsy in Karaj city. Twenty-Seven children with spastic CP (level GMFCS I-III) with age of 8-14 years were selected as sample and were divided randomly into intervention and control group The intervention group followed an 12 weeks (three sessions per week) of resistance exercise program to strengthen the muscles the lower extremity and the control group continued their daily routines. In order to measure the spasticity were used from the Modified Ashworth Scale, muscle strength from 30second lateral Step up and to sit to stand to measure walking speed from the time 10 meter walk test, 1 minute fast walk test were used. Results: The results not showed a significant difference in total mean spasticity after the training period in the intervention group than the control group (P> 0/05). But there was a significant increase in functional muscle strength and walking speed in the intervention group which was significant than the control group (P <0. 05). Conclusions: Applying a resistance exercise with exciting music by providing conditions for increased motivation and participation can be an effective way to improve the motor function of children with cerebral palsy of spastic.