The purpose of this study is to find out the acoustic characteristics of produced alveolar sibilant sounds according to the subsequent vowels of the children with cerebral palsy through acoustic analysis. Ten children with spastic cerebral palsy aging from 6 to 10 years old were selected by an articulation test and compared with a control group of twenty children. The frication duration of alveolar sibilant sounds and the subsequent vowel duration were measured from the disyllable VCV and the frame sentence including target syllables CV which were analyzed by using Multi-Speech. As a result, the children with cerebral palsy had significantly shorter frication duration of lenis-tensed alveolar sibilant than the control group in the high vowel, mid vowel, low vowel, central vowel and back vowel following the alveolar sibilant sounds of VCV and the frame sentence(p<.05). The children with cerebral palsy had significantly longer duration of mid vowel, central vowel and back vowel following lenis-tensed alveolar sibilant than the control group in VCV and the frame sentence(p<.05). The frication duration of the children with cerebral palsy showed significant differences between the lenis and tensed in all kinds of vowel following the alveolar sibilant sounds of VCV and the central vowel following the alveolar sibilant sounds of frame sentence(p<.05). The subsequent vowel duration showed significant differences between the lenis and tensed in the vowel duration of high vowel, mid vowel, frontal vowel, and back vowel of VCV(p<.05). The results will be fundamental data intervened to the articulation treatment of alveolar sibilant sounds for children with cerebral palsy.