The aim of this study was to understand the dynamics of multidimensional poverty and its determinants among mid-aged and older adults. We used 2011, 2013, 2015, and 2018 data from the China Health and Retirement Longitudinal Study. We utilised basic descriptive statistics, the poverty transition matrix, Kaplan–Meier estimates, and the discrete-time proportional hazards model for data analysis. From 2011 to 2018, the incidence of multidimensional poverty among mid-aged and older people basically decreased, but the average poverty intensity remained stable. Most mid-aged and older adults had transient multidimensional poverty. The longer an individual remained multidimensionally poor, the smaller the probability of exit from poverty; The longer an individual remained nonpoor after escaping from poverty, the smaller the probability of returning to poverty. As to other factors, individual characteristics, family structure, living arrangements, social capital, and living areas significantly affected the risks of multidimensional poverty exit and reentry. Based on these results, the government should implement targeted interventions for frail older adults with the identified characteristics to prevent them from persistent multidimensional poverty or return to poverty.