The rich ecological resources in underdeveloped resource-rich areas are difficult to transform into economic advantages under the system of low-cost resources, a priceless environment and highpriced industrial products, resulting in a backward economic development level, serious relative poverty and a possible return to poverty at any time. Correctly evaluating the effect of green poverty reduction in underdeveloped resource-rich areas holds great significance for reducing relative poverty and ending the phenomenon of returning to poverty. Taking Jiangxi Province as an example, this paper uses the entropy weight method and the coefficient of variation to calculate the green poverty reduction index and each subdimension index of 80 counties (cities/districts) in Jiangxi Province, and analyzes the characteristics of the province’s spatial and temporal evolution. It is found that the green poverty reduction index of Jiangxi Province rises overall, but the regional differences are obvious, and the increase in each subdimension index leads to an increase in the green poverty reduction index. The increase in the economic poverty reduction index is the main reason. The regional differences will persist, and balanced development will not be achieved in the short term.