Ponds near canal embankment is a severe hidden danger affecting the safety of river canal project. With a river slope involving ponds and expansive soil in the Yangtze-to-Huaihe River Diversion Project as a case study, a numerical model coupling seepage and stability analysis for river slope was established by using GeoStudio software. Reinforcement measures were proposed, and the anti-sliding stability of the studied river slope before and after reinforcement was analyzed. Furthermore, the effects of pond filling treatment, pond water depth and soil permeability on the seepage and stability of the river slope are investigated. Results manifest that the reinforced river slope meet the requirements of stability specification under various working conditions. Pond filling treatment reduces remarkably the elevation of water outflow point of the pond and the unit width flow of leakage, hence improving the stability of river slope. Under the conditions considered in the present study, the water depth of the pond had little effect on the pond’s water seepage as well as the stability of the river slope. The permeability of expansive soil has a significant impact on the pond’s water seepage as well as the stability of river slope. Specifically, lower permeability coefficient of expansive soil results in lower water outflow point, lower unit width flow of leakage and higher safety factor for the river slope.