In order to explore the settlement and deformation characteristics of the foundation of the embankment filled with foam lightweight soil，the vertical additional stress of foundation was deduced using the numerical integration method，and a theoretical calculation model for foundation settlement of light soil embankment was proposed combined with hierarchical summation method. And the engineering example analysis was carried out，based on a foam lightweight soil embankment project on Guanglian Expressway. The results showed that，caused by the action of the foam light soil embankment，the theoretical settlement value of the foundation is distributed in a V-shaped curve in the horizontal direction，and the settlement at the center of the embankment is maximum. The closer to sides of embankment，the smaller the settlement of foundation. The overburden load of the foundation soil can be reduced by the foam light soil，reducing the overall settlement. The theoretical value of foundation settlement is in good agreement with the field measured data. Therefore，the rationality of the settlement calculation method is verified. This study can provide reference for the design and construction of light soil subgrade.