Background: Based on the Stereotype Embodiment Theory (SET), this study aims to examine the mechanism of ageism on frailty through the proposed framework of “Experiences of Ageism (EA) → Age Stereotypes (AS) → Attitudes to Ageing (AA) → Frailty” using a structural equation model (SEM).Methods: A community-based study involving 630 participants aged 60 years and older was conducted in Shanghai. EA, AS, AA and frailty status were assessed by validated scales. In particular, EA included three parts in this study, as the first part was the experiences of explicit prejudice or discrimination because of age, another two parts were the experiences of witnessed and encountered implicit negative age-based stereotypes. A SEM was performed to examine whether the proposed paths from EA to frailty were supported.Results: EA had a significant indirect effect (β’ = .360*-.456*-.576 = .095,p < .001) on frailty through the path of “EA → AS → AA → Frailty” after controlling for covariates. AA had a direct effect (β = −.576,p < .001) on frailty; AS fully mediated the association between EA and AA (indirect effect = .360*-.456 = −.164,p < .001), and AA fully mediated the association between AS and frailty (indirect effect = −.456*-.576 = .263,p < .001).Conclusions: These findings demonstrated a mechanism from ageism to frailty, and highlighted the potential threat of negative AS on health. Ageism and frailty are both great challenges for the process of healthy ageing.