The purpose of this study was to compare phonological awareness ability of students with Down Syndrome(DS) and typically developing children(TD). TD and DS were equal the reading abilities(reading recognition). The subject were 10 DS and 10 TD, and were examined by test of phonological awareness. The test of phonological awareness was composed according to phonological units(word, syllable, phoneme) and task types(deletion, discrimination, blending). The results obtained in this study were as follows: The total score of phonological awareness ability of DS were significantly lower than TD. And the score of phonological awareness ability according to phonological units and task types were significantly lower than TD. But both DS and TD performed better on phonological deletion and blending task than discrimination. TD and DS represented different correlation between task types and phonological units. This means that TD performed better on all types of tasks and phonological units than DS.