Foam lightweight soil and geogrids play an important role in the treatment of soft soil subgrade diseases in mountainous areas. There are great limitations in the application of foamed lightweight soil alone. As a deepening and supplement to previous research, combining the advantages of foam lightweight soil and geogrids to study the deformation of reinforced foam lightweight soil embankments is of great significance for highway engineering. Full-scale model tests were conducted to study the deformation of foam lightweight soil embankments and reinforced foam lightweight soil embankments. The results show that using reinforced foam lightweight soil embankments can reduce settlement and more effectively decrease subgrade stress and earth pressure, while also helping to spread the base soil pressure and solve the problem of uneven distribution of base stress. Therefore, adopting reinforced foam lightweight soil embankments can improve the bearing capacity of soft soil subgrades and enhance the stability of the subgrade.