Foamed asphalt has been widely applied in road engineering due to its environmentally friendly advantages in low-temperature construction. However, its adhesion performance with aggregates critically affects the stability of pavement structures. This study investigates the adhesion characteristics of foamed asphalt on virgin aggregates and reclaimed asphalt pavement (RAP) materials using a multi-scale analysis approach that integrates scanning electron microscopy (SEM) and image segmentation techniques. By varying the water content, asphalt temperature, and aggregate temperature, the study systematically analyzes the effects of these factors on the spread coverage and microstructure of foamed asphalt. The results indicate that aggregate temperature has the most significant impact on adhesion performance, with higher temperatures enhancing the spreading ability and microstructural stability of foamed asphalt. Water content ranks second, as a moderate increase in water content improves spreadability, while asphalt temperature has a relatively smaller effect. Additionally, the residual aged asphalt film on RAP surfaces weakens the adhesion performance of foamed asphalt, but proper surface treatments can significantly improve this property. This study proposes a novel analysis method combining SEM and image segmentation, providing a new tool for research on foamed asphalt adhesion performance and theoretical support for the utilization of recycled materials and optimization of construction techniques.