The influence mechanism of foam fluid on the seepage in the embankment foundation and the development of embankment seepage failure are unclear. In this study, the seepage failure experiment without foam fluid and the seepage failure experiment with foam fluid are carried out to investigate the characteristics of seepage in soil during the development of seepage failure and the influence of foam fluid on soil seepage. The experimental results show that foam fluid has a significant impact on the seepage in soil. The flow resistance greatly increased by the foam bubble trapped in pores, while the soil is turned to unsaturated state, which leads to the enhanced impervious performance. Besides, the flow path becomes longer due to the existence of foam fluid, which reduces the hydraulic gradient, and in turn significantly restrains the development of seepage failure of the embankment foundation.