With　the　development　of　the　economy　and　living　standard,　people＇s　food　expense　idea　has　changed　from　the　traditional　to　the　modern　age.　In　food　trade,　degree　of　perfection　of　the　food　chain　has　played　an　important　role　in　the　development　of　food　safety　and　food　profession.　By　investigation　of　the　third-part　cold-chain　logistics　distribution　in　Beijing,　comparative　experiment　was　conducted　under　complete　and　incomplete　degree　cold　chain　conditions.　The　change　of　temperature　in　the　whole　process　was　recorded　by　RHLOG-T　temperature　auto-recorder.　According　to　the　data　collected,　we　can　see　that　the　heat　flow　of　food　under　incomplete　degree　cold-chain　condition　is　remarkable　compared　with　complete　degree　cold-chain　condition.　Exemplified　by　the　process　of　the　third-part　cold-chain　logistics,　under　incomplete　degree　cold-chain,　the　heat　flow　of　the　frozen　pork　and　the　ice　cream　respectively　increased　36.9%　and　101.8%　compared　with　the　complete　cold-chain.　In　conclusion,　measures　to　keep　food　cold　chain　perfect　is　necessary.