Electrophysiological approach was used to examine effects on the amplitude and latency of segmental and suprasegmental (speech prosody) phonological units MMNs in response to consonant-vowel (CV) syllables in lexical tones. There was significant difference in amplitude and latency for MMNs between phonological units. Our result suggests that the MMN responses to the suprasegmental (speech prosody) phonological unit were greater than the segmental phonological unit. These data are relevance to a growing number of researches of MMN effects in response to changes of speech prosody in normal adults.