<p>The Gansu-Qinghai contiguous region of the upper Yellow River is located in the transition zone between the Loess Plateau and the Qinghai-Tibet Plateau, characterized by fragile ecosystems and high sensitivity to climate change. As a critical ecological security barrier and water conservation area, it faces persistent tensions between development demands and ecological protection. Quantitative assessments of how production-living-ecological space (PLES) evolution affects ecological and environmental quality (EEQ) under long-term, multi-scenario conditions remain limited in such vulnerable regions. Understanding PLES-EEQ relationships is essential for optimizing territorial spatial planning and maintaining ecological security in the Yellow River basin. This study utilized land use data from 2000 to 2020 and the FLUS model to simulate PLES evolution from 2030 to 2060 under SSP1, SSP2, and SSP5 scenarios. The analytical framework integrated artificial neural networks and cellular automata with Shared Socioeconomic Pathways to project spatial configurations and assess EEQ in 2035. Living space expanded across all three scenarios while ecological space decreased. Production space increased by 125 km² under SSP5 but declined in other scenarios. The EEQ index in 2035 showed improvements relative to the baseline value (0.4130) in 2020. Medium-to-high quality areas were primarily grassland and forest, whereas low-quality areas consisted mainly of unused land concentrated in the central and western regions. This study reveals a nonlinear relationship between ecological space quantity and quality, showing that structural optimization can enhance EEQ despite area reduction. The findings suggest that strengthening ecological protection redlines and restraining urban expansion are essential for territorial spatial optimization in ecologically fragile regions.</p>