Purpose : The present study has been performed to find the effects on gross motor function and balance ability of applying a balance exercise program consisting of motions able to stimulate balance-related sensory systems on various support surfaces along with goal-oriented upper extremity tasks to enhance the balance ability. Methods : 10children diagnosed as having spastic diplegia were selected as the subject for this study, of whom 5children were randomly assigned to a control group (CG) and the remainder to a balance exercise group (BEG) to perform the upper extremity task on various support surfaces. Each intervention was executed 30minutes per session with 2sessions a week for 12weeks. To make comparisons before and after intervention, gross motor function measure; standing; demention D(GMFM;D), walking/running/jumping ;demention E (GMFM;E) and pediatric balance scale (PBS) were evaluated. Results : The CG showed a significant difference (p<.05) in GMFM;E. BEG showed a significant difference (p<.05) in GMFM;D as well as GMFM;E and in PBS before and after intervention. BEG showed a significant improvement (p<.05) in GMFM;D and the PBS compared with the CG whereas it did not indicate any statistically significant difference in GMFM;E. Conclusion : According to the results of this study, it has been shown that a balance exercise accompanied by upper extremity task on various support surfaces had an effect on improvement in the gross motor function and the balance ability of children with spastic diplegic cerebral palsy.