This　work　describes　the　uncertainty　and　sensitivity　analysis　results　based　on　ATHAS(Advanced　Thermal　Hydraulics　Analysis　Subchannel)　thermal　hydraulic　subchannel　code,　which　is　developed　by　Xi’an　Jiaotong　university.　PSBT　benchmark　has　been　simulated　with　the　ATHAS　code,　and　the　temperatures　of　subchannel　outlets　are　selected　as　the　output　of　interest.　In　addition,　model　inputs　can　be　considered　as　following　three　categories,　including　geometric　effect,　boundary　conditions　and　initial　conditions.　In　this　paper,　local　sensitivity　and　global　sensitivity　analysis　are　performed,　respectively,　also　have　compared　their　results.　Local　sensitivity　analysis　methods　used　in　this　work　include　OAT(one-factor-at-a-time),　Latin　Hypercube　Sampling　and　rank　correlation　coefficient;　Global　sensitivity　analysis　used　in　this　work　include　Morris　screening　and　Sobol　analysis,　also　implement　their　optimization　plan.　The　global　sensitivity　analysis　is　compared　with　the　local　sensitivity　analysis　results,　sensitivity　parameters　are　basically　consistent,　except　the　interaction　effect　of　input　parameters.　Furthermore,　the　results　of　this　work　indicate　that　under　the　uncertainty　range　of　inputs　parameter,　geometric　effect　and　boundary　conditions　has　significant　contribution　to　the　uncertainty　of　the　output,　moreover,　the　most　influential　parameters　in　geometric　effect　and　boundary　conditions　is　pitch　and　inlet　mass　velocity,　respectively.　©　2019　American　Nuclear　Society.　All　rights　reserved.