Abstract: Chinese dialects exhibit a unique historical phonological — lexical phenomenon known as literary and vernacular pronunciations. The Chengdu dialect, in its formation, is a blend of the dialects of ancient Sichuan, Shaaxi and Shanxi, as well as the dialects of immigrants from various places during the Ming and Qing dynasties, leading to a complex pattern of language contact. The coexistence of literary reading and vernacular reading for the same Chinese characters reflects the interaction of different pronunciations in the process of language contact, a synchronic phenomenon resulting from diachronic shifts of pronunciation in accordance to context, style, and usage. The study of the pronunciation variants in Chengdu dialect is a key topic within the broader context of Southwest Mandarin and Northern dialects. This paper examines the "use" and "change" of literary and vernacular pronunciations of Chengdu dialect. "Use" refers to the phonetic forms and word distribution of these variants, while "change" refers to the competitive phonetic shifts and sociolinguistic variations that occur during their usage, encompassing both linguistic and social distribution across different social groups. The study concludes that the two variant pronunciations reflect the different daily "use" of Chengdu dialect in meeting variant functional needs, whereas "change" signifies socialized phonetic differentiations resulting from the influence of social factors.