Although extreme poverty has been eradicated in China, older adults in empty-nest households may risk falling into or returning to poverty in the future. Previous studies on poverty alleviation had focused on the measurement of ex-post poverty at a particular time. Few studies have assessed households’ vulnerability to poverty from a forward-looking perspective. This study aims to identify the vulnerability to poverty and its determinants among rural empty-nest households with older adults. A total of 1,951 rural empty-nest households with older adults followed for one year were included in the analysis. The Three-stage Feasible Generalized Least Square method was used to estimate the vulnerability to poverty in 2019 and 2020. A regression model was used to explore the effect of different factors on vulnerability to poverty, and Shapley values were used to decompose each factor’s contribution and the attributable percentage. With the increase of the poverty threshold, the success rate of predicting poverty status in 2020 based on poverty vulnerability in 2019 increased from 33.00% to 63.71%. Regardless of the poverty threshold, the vulnerability to poverty incidence decreased from 2019 to 2020. For example, under the Shandong province poverty line, the estimated proportion of rural empty-nest households with older adults vulnerable to poverty had decreased from 15.63% in 2019 to 11.17% in 2020. The Shapley decomposition results suggested that the number of the household labor force, the interviewees’ education and age, and household size were the four most influential factors that contributed significantly to the poverty vulnerability. This study reveals that a portion of rural empty-nest households with older adults are still vulnerable to poverty. The formulation of future anti-poverty policies should prioritize these groups and adopt targeted poverty prevention and poverty alleviation measures based on the driving factors of poverty vulnerability among rural empty-nest households with older adults.