In　order　to　develop　the　research　on　129I　transmutation　in　the　thermal　reactor,　127I　target　was　irradiated　in　Xi＇an　pulsed　reactor　(XAPR)　to　explore　the　condition　for　experiment　in　XAPR.　The　Monte　Carlo　method　was　used　in　the　calculation　of　127I　target　transmutation　rate,　and　the　results　were　compared　with　the　experimental　data.　The　NJOY　software　was　used　to　generate　127I　ace　format　neutron　cross　section　at　XAPR　operating　temperature　based　on　ENDF/B　VII.　0　library.　New　cross　section　was　compared　with　old　ENDF/B　VI　library　and　developed　in　the　unresolved　resonance　region.　MCNP　was　used　to　modify　the　127I　cross　section　of　ORIGEN2　by　adopting　a　new　cross　section,　then　transmutation　of　127I　target　was　calculated　to　analyze　changes　of　transmutation　rate　and　nuclides,　also　the　influence　of　neutron　spectrum　and　irradiating　time　on　transmutation　was　studied.　The　CINDER＇90　software,　a　depletion　mode　of　MCNPX,　was　also　used　to　model　the　transmutation　condition,　the　analytical　result　was　consistent　with　ORIGEN2,　but　was　a　little　different　from　the　experimental　data　(2%-3%　error)　because　of　the　deviation　from　the　MCNP　model　in　neutron　flux　calculation.