The　dual　heat　source　coupling　modes　of　solar-ground　source　heat　pump　system　(SGSHPS)　directly　determine　its　operation　characteristics.　In　this　paper,　the　thermal　performance　of　a　SGSHPS　operated　in　different　dual　heat　source　coupling　modes　were　studied　experimentally.　The　unit　COP,　solar　collecting　efficiency　and　inlet　and　outlet　temperatures　of　GHE　were　tested　for　various　modes.　The　results　show　that　for　the　combination　operation　mode,　solar　and　ground　heat　source　are　dynamically　coupled　by　the　water　tank　and　plate　heat　exchanger,　and　the　average　unit　COP　and　collecting　efficiency　are　3.61　and　51.5%,　respectively.　For　the　water　tank　heat　storage　mode,　the　inlet　water　temperature　of　evaporator　in　the　daytime　stop　mode　of　GSHP　is　1.85　degrees　C　higher　than　daytime　operation　mode　of　GSHP,　and　the　average　unit　COP　and　collecting　efficiency　are　respectively　3.43　and　34.8%,　3.91　and　34.9%　for　the　daytime　stop　mode　of　GSHP　and　daytime　operation　mode　of　GSHP.　For　the　ground　heat　storage　mode,　the　ground　temperature　can　be　improved　effectively　for　ground　continuous　heat　storage　mode　and　the　outlet　temperature　of　GHE　can　be　increased　significantly　for　ground　intermittent　heat　storage　mode.　The　average　unit　COP　and　collecting　efficiency　are　3.65　and　47.9%,　3.8　and　41.5%　for　the　ground　intermittent　and　continuous　heat　storage　mode,　respectively.　A　TRNSYS　dynamical　simulation　model　of　the　SGSHPS　was　established　to　explore　the　influences　of　key　parameters　on　the　system　performance.　The　results　indicate　that　the　collector　area　and　GHE　number　have　evident　influences　on　the　system　efficiency,　but　the　impact　of　water　tank　volume　is　very　small.　The　suitable　collector　area　and　GHE　number　are　found　to　be　80　m(2)　and　9,　respectively,　and　the　water　tank　volume　should　be　set　as　small　as　possible　with　the　permission　of　actual　conditions.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.