The　main　challenge　in　the　analysis　of　unconfined　seepage　flow　is　that　the　position　of　free　surfaces　is　unknown　a　priori,　which　needs　to　be　determined　through　a　series　of　iterative　processes.　The　numerical　manifold　method　(NMM)　is　a　promising　method　which　uses　a　dual　cover　system　consisting　of　both　mathematical　and　physical　covers.　Compared　with　those　traditional　methods,　NMM　is　characterized　by　meshing　convenience,　approximation　accuracy,　and　being　capable　of　coping　with　free　boundary　value　problems.　Unlike　the　traditional　NMM　where　the　material　interface　participates　in　cutting　the　mathematical　cover　while　forming　the　physical　cover,　the　physical　patches　in　this　study　can　contain　the　material　interface.　The　new　weight　functions　for　such　physical　patches　are　constructed　using　the　refraction　law,　followed　by　the　application　to　the　analysis　of　unconfined　seepage　flow　problems.　By　comparing　with　analytical　or　reference　solutions　of　some　classic　examples,　it　is　validated　that　the　proposed　method　can　accurately　locate　the　free　surface,　demonstrating　its　accuracy　and　convenience　in　solving　unconfined　seepage　problems.