Controlling rocky desertification while mitigating rural poverty is essential for promoting sustainable development, especially for developing countries. Obtaining data from the Earth Observing System of NASA (The National Aeronautics and Space Administration), this study applies comprehensive index analysis, linear regression modeling, and spatial autocorrelation techniques to investigate the spatiotemporal evolution and trade-off / synergistic relationships between farmers' livelihood capacity (FLC) and net primary production (NPP) in the Yunnan-Guangxi-Guizhou rocky desertification region in China from 2000 to 2020. The results show that: (1) While poverty alleviation efforts had achieved significant long-term success, challenges remained in reaching rural revitalization targets. The FLC index grew steadily from 0.287 in 2000 to 0.354 in 2020, yet overall levels remained relatively low. (2) FLC exhibited significant spatial disparities, where high-value clusters were concentrated in southern and southeastern Guangxi, and low-value zones shifted gradually from northern Guizhou to southwestern Yunnan. (3) Rocky desertification control yielded positive outcomes, though ecological civilization construction required continued effort. Regional NPP experienced a fluctuating increase from 878.88 gC m-2a-1 to 908.60 gC m-2a-1 during 2000 and 2020, with an average annual growth rate of 1.486 gC m-2a-1, indicating steadily improving carbon sequestration capacity. (4) The spatial patterns of NPP remained generally stable while significant regional variation existed. High-value areas were mainly located in southwestern Yunnan, while medium-high and low-value zones distributed across southern Guangxi and northern Guizhou. (5) Although spatial correlation analysis indicated generally positive relationships between FLC and NPP, the synergistic relationship between FLC and NPP was weakened since 2015, and the clustered spatial pattern also became scattered.