The　numerical　modeling　of　pile-soil　dynamic　interaction　has　been　a　challenging　problem　in　engineering　for　many　years　because　of　the　unbounded　domain,　which　typically　involves　significant　computational　cost.　This　paper　develops　a　novel　scaled　boundary　finite　element　method　(SBFEM)　that　can　accurately　calculate　the　soil　dynamic　impedance　of　pile　groups　with　end　bearing　subjected　to　horizontal　vibration.　The　three-dimensional　(3D)　problem　is　first　transformed　to　a　two-dimensional　(2D)　Helmholtz　equation　in　the　horizontal　plane,　exploiting　the　analytical　solution　for　the　vertical　modes　using　separation　of　variables.　The　SBFEM　is　then　applied　to　solve　the　2D　computational　domain,　which　is　divided　into　bounded　and　unbounded　domains.　Based　on　the　SBFEM,　an　accurate　circular　artificial　boundary　condition　(ABC)　is　formulated　to　simulate　the　unbounded　domain　of　the　soil.　A　special　hybrid　quadtree　mesh　is　devised　for　this　problem,　where　a　high-quality　structured　quadrilateral　mesh　is　generated　surrounding　the　piles.　The　accuracy　of　the　proposed　method　is　verified　using　a　single　pile　problem　with　known　analytical　solution.　The　effects　of　dimensionless　frequency,　pile　numbers,　soil　depth　and　relative　distance　between　piles　on　the　soil　dynamic　impedance　are　considered.