Using prefecture-level policy documents (2008–2018) and the China Health and Retirement Longitudinal Study (2011–2018), this study used fixed-effects regressions to examine the associations between the maturity of two age-friendly policies, i.e., old age care (OAC) and preferential treatment (PT) policies for older adults, and the self-rated health (SRH) of older adults. We use policy duration and policy density to measure policy maturity. The results showed positive relationships exist between the density of OAC and PT policy and older adults’ SRH, whereas long policy duration often relates to lower SRH. Policy duration and policy density work synergistically. Furthermore, heterogeneity analyses indicated that older adults aged over 75 years, male, those with physical or mental impairment, and living in rural areas and in the first- and second-tier cities benefit significantly from denser OAC policy. The SRH of older adults suffering from physical disabilities or mental problems and living in rural areas is positively associated with denser PT policy. From a policy perspective, our findings suggest that age-friendly policies should be updated over time and be place- and characteristic-tailored.