The　imbalance　of　heat　extracted　from　the　soil　by　the　ground　heat　exchangers　(GHEs)　in　winter,　and　rejected　into　it　in　summer　is　expected　to　affect　the　long-term　performance　of　ground　source　heat　pump　(GSHP)　in　areas　of　southern　China.　This　chapter　presents　a　new　operation　mode　to　resolve　this　problem　that　in　summer　night　the　intermittent　operation　of　GHEs　with　the　cooling　tower　as　the　supplemental　heat　rejecter　of　GSHP　system　and　in　transition　seasons　the　coupling　operation　of　cooling　tower　combined　with　the　GHEs.　The　practical　analytical　model　of　GHEs　based　on　the　line-source　theory　is　established.　The　computer　program　based　on　established　model　is　developed　to　do　the　feasibility　analysis　under　the　proposed　operating　mode　for　a　GSHP　system　in　Nanjing　of　southern　China.　The　results　indicate　that　the　imbalance　problem　of　the　rejected/extracted　heat　for　the　GSHP　system　in　Nanjing　of　southern　China　is　effectively　resolved.　In　addition,　under　the　proposed　operating　mode　the　COP　of　heat　pump　unit　can　be　improved,　design　capacity　of　cooling　tower　can　be　reduced　and　utilization　rate　of　cooling　tower　throughout　the　year　can　also　be　increased.　The　results　can　improve　the　energy　efficiency　of　GSHP　system.