The pore structure of concrete face slabs is a critical microstructural factor governing their mechanical properties and durability performance. To clarify the influence of high-temperature and low-humidity coupled environments on the pore structure of face-slab concrete, this study employed nuclear magnetic resonance (NMR) technology to investigate the distribution characteristics and evolution patterns of concrete pore structures under high-temperature and low-humidity curing conditions. The results indicate that significant differences exist in the pore distribution and evolution behavior of concrete subjected to different curing environments. Under standard curing conditions, the internal hydration reaction proceeds continuously and sufficiently, leading to a rapid decrease in total porosity with age; capillary pores and large pores gradually transform into gel pores, and the pore structure evolves rapidly toward a dense state. In contrast, under high-temperature and low-humidity curing, accelerated evaporation of free water and insufficient subsequent humidity suppress hydration reactions, hinder the refinement of capillary pores, and cause large pores and micro-cracks to persist at high levels throughout the curing process. As a result, the pore structure exhibits a “stabilized coarsening” pattern and fails to achieve a dense microstructure, ultimately contributing to strength degradation and reduced durability of the concrete. The findings of this study provide theoretical support and technical guidance for the design, construction, and maintenance of concrete face slabs in hot and arid regions, thereby contributing to enhanced engineering safety.