A　novel　integrated　system　of　vapor　compression　and　pump-driven　two　phase　loop　for　energy　saving　in　data　centers　cooling　is　presented　in　this　paper.　In　the　new　system,　the　vapor　compression　mode　works　at　the　hot　outdoor　temperature　and　the　pump-driven　mode　operates　at　the　cold　outdoor　temperature.　An　experimental　bench　was　constructed　using　a　3　HP　compressor　and　a　1　HP　compressor　in　the　integrated　system,　respectively.　The　results　show　that,　the　new　system　has　a　better　performance　for　application　in　data　centers,　the　maximum　cooling　EER　of　the　integrated　system　can　reach　to　29.71.　The　most　suitable　outdoor　temperature　for　switching　the　modes　was　also　obtained　from　the　experiment.　It　is　recommended　to　design　the　integrated　system　based　on　the　cooling　performance　of　the　pump-driven　two　phase　loop.　(C)　2015　Published　by　Elsevier　Ltd.