Based　on　a　quasi　3-D　steady　model　inside　and　a　2-D　unsteady　model　outside　of　the　borehole　of　ground　heat　exchanger(GHE),　the　relationship　between　the　heat　exchange　rate　per　depth　of　borehole　and　main　parameters　(center-to-center　distance　of　two　branch　pipes,　radius　and　depth　of　the　borehole)　has　been　analyzed.　The　rational　values　of　those　design　parameters　with　considering　the　heat　exchange　rate　per　depth　of　borehole　are　obtained.　The　dynamic　simulations　of　underground　temperature　field　(UTF)　of　single-pipe　and　pipe-group　of　U-tube　GHE　have　been　conducted　by　ANSYS.　The　change　rules　of　UTF　are　obtained　when　ground　source　heat　pump(GSHP)　has　experienced　a　complete　cooling　and　heating　cycle　during　one　year.　The　simulation　results　of　a　single-pipe　show　that　the　action　radius　of　borehole　is　1.9　m,　i.e.,　it　is　reasonable　that　the　borehole　center-to-center　distance　is　3.8　m.　The　simulation　results　of　pipe-group　indicate　that　temperature　of　the　soil　center　encircled　by　four　boreholes　at　the　beginning　of　heating　in　winter　is　higher　than　the　initial　temperature　of　soil,　but　it　is　in　opposite　for　cooling　in　summer,　which　is　beneficial　to　the　efficient　operation　of　GSHP.　This　work　can　provide　guidance　for　the　rational　design　and　operation　of　GSHP.　(C)　2019　Elsevier　Ltd.　All　rights　reserved.