In　this　study,　the　Exergy　analysis　of　the　shell　and　helically　coiled　tube　heat　exchanger　(SHCTHX)　were　investigated.　The　heat　transfer　Exergy　loss　of　the　SHCTHX　implemented　by　MATLAB　software　was　developed,　where　the　dimensionless　number　named　heat　transfer　Exergy　loss　number　(xi　HT)　was　proposed.　The　effect　of　parameters　(core　tube　diameter　(DC),　space　between　the　shell　and　the　core　tube　(Delta　DBC),　inner　diameter　of　coiled　tube　(di),　thickness　of　the　coiled　tube　(dt)　and　mass　flow　rate　(Mshell))　on　the　effectiveness　(epsilon),　heat　transfer　Exergy　loss　number　(xi　HT)　and　number　of　transfer　unit　(NTU)　were　investigated.　Moreover,　the　optimization　of　the　SHCTHX　was　studied.　When　the　design　parameters　are　set　as　DC,　Delta　DBC,　di,　and　dt,　there　is　coincidently　opposite　variation　trend　for　xi　HT　and　epsilon,　the　optimization　results　of　which　are　identical.　When　the　design　parameters　are　set　as　DC,　Delta　DBC,　di,　dt　and　Mshell,　the　effectiveness　(epsilon)　of　optimization　results　with　xi　HT　is　30%　larger　than　that　without　xi　HT;　while　the　heat　transfer　area,　the　overall　heat　transfer　coefficient,　the　needed　mass　flow　rate　and　the　heat　transfer　irreversible　loss　of　optimization　results　with　xi　HT　have　reduction　of　30%,　15%,　30%　and　10%　than　those　without　xi　HT.