Although the use of rhythm metrics in evaluating rhythm class hypothesis is debated nPVI can effectively reflect rhythm difference when applying to closely related languages and several methods can further improve the robustness. The current study shows that Chengdu Mandarin as a tone language has a much larger nPVI than standard Mandarin and is closer to typical stress-timed languages like English. The rhythm pattern is corroborated by the salience of stress in Chengdu Mandarin. Most disyllabic and trisyllabic words carry word-initial stress marked by lengthened duration. Informational focus is also realized through durational change along with pre-focus compression and lengthening on paricles. The acoustic properties of tones and tone-sandhi patterns are also closely associated with the realization of stress. The study of rhythm can therefore shed new light on the long-debating question of the occurence of lexical stress in tone languages.