Abstract:The literal and colloquial differences of pronunciation is an overlapping phenomenon caused by the contact of different dialectsas Such phenomenon exists in various languages and dialects. In essence, it reflects the different historical phonetic levels. Such differences in the vowels of Xichong dialect have shown the permeation of Chengdu and Nanchong dialects. well as the different historical levels of the relevant speech sounds. And it has offered a clue to the phonetic change. Through comparison between the literal and colloquial languages, and between dialectal accents, we can find not only the literal and colloquial differences of Xichong dialect, but the value for the theory and method of studying phonology of the dialect.