This essay analyzes “zi” trills in Yicheng dialect from the perspective of experimental phonetics and discusses their variation and development in light of social linguistics. Results show that “zi” trills are not independent syllables, but clitic elements to the preceding syllables. “Zi” trills can’t be independent, nor be syllables themselves. No plosives or affricates are detected between “zi” trills and the preceding syllables. The vibration frequency of “zi” trills is lower than that of Russian trill р and the tongue position of “zi” trills is slightly higher and further back than Russian trill р. The figure of intensity，pitch and duration of “zi” trills is smaller than that of the preceding syllables on the whole. Tone has impacts on “zi” trills. Especially when the syllable ahead is toned as yin ping, “zi” trills will be strengthened. Hearing test shows that “zi” trills can’t bear stress. Prosodic phonology analysis reveals that each “zi” trill occupies one mora only. The analysis of “zi” trills in Yicheng dialect exhibits their acoustic performance, proving more and detailed evidences for the neutralization of suffixes, as well as enriching the types and approaches of rhyme variation. Under the influence of linguistic context, “zi” trills in Yicheng dialect are varying profoundly: in adolescents’ pronunciation, “zi” is coverted from trill into flap or lateral, even dropped. The roadmap of the evolution of “zi” trill in Yicheng dialect is predicted by this essay as follows: r>/l> .