Driven by global sustainable development strategies, China, as a major infrastructure nation, faces multiple pressures from resource constraints, environmental challenges, and its dual carbon goals. The efficient recycling of recycled asphalt pavement (RAP) has become a core issue for the green development of road engineering. Traditional recycling technologies struggle to overcome the 30% blending bottleneck due to issues such as high RAP agglomeration rates and significant gradation variability. Oil-stone separation technology deconstructs RAP to a near-virgin state through physical crushing, offering a novel pathway for high-ratio (≥30%) and even ultra-high-ratio (≥50%) RAP recycling. This paper critically reviewed systematic research on RAP material properties, oil-stone separation technology, and plant-mixed hot recycling applications by comparing domestic and international progress. It focused on exploring agglomeration mechanisms, causes of variability, and control strategies, while analyzing the root causes of performance controversies in recycled mixtures. Finally, the paper identified current research gaps in mechanism depth, technological intelligence, standard systems, and long-term performance validation, proposing future research directions to provide theoretical guidance for advancing asphalt pavement recycling technology toward high efficiency, high value, and low-carbon development.