In　the　present　study,　the　shell-side　flow　and　heat　transfer　characteristics　of　shell-and-tube　dry　expansion　evaporator　with　continuous　helical　baffles　were　studied　by　Computation　Fluid　Dynamic　(CFD)　method.　The　results　indicated　that,　for　the　same　volume　flow　rate,　the　j　factors　and　f　factors　of　evaporator　with　continuous　helical　baffles　were　only　1/3　and　1/4　of　the　evaporator　with　segmental　baffles.　However,　the　comprehensive　performance　j/f　factor　had　57%　increases.　If　the　maximal　velocity　ratio　was　higher　than　2.4,　the　continuous　helical　baffles　evaporator　can　have　higher　shell-side　heat　transfer　coefficient　than　the　segmental　baffles　evaporator.