In　the　era　of　big　data,　the　requirement　for　information　security　and　system　reliability　has　become　more　and　more　strict.　There　are　some　disadvantages　in　the　application　of　the　existing　universal　data　backup　and　synchronization　scheme　to　the　data　storage　of　the　key　server　(The　security　problems　in　data　transmission　and　the　synchronization　problem　in　the　case　of　the　primary　is　not　connected　to　the　secondary).　In　this　paper,　according　to　the　traditional　multi　machine　backup　technology,　a　data　synchronization　scheme　is　proposed　based　on　the　private　cloud　key　server.　It　effectively　solves　the　problem　of　data　synchronization　in　the　case　of　the　primary　and　the　secondary　is　not　connected.　Meanwhile,　in　the　process　of　data　transmission,　the　method　that　extends　the　PKCS#7　international　encryption　standard　is　proposed　to　support　domestic　encryption　algorithm.　In　this　way,　it　conforms　to　the　State　Cryptography　Administration　standard　and　improves　the　security　of　data　transmission.　©　2016　IEEE.