In　order　to　study　the　ultra-low　cycle　fatigue　(UCLF)　behavior　of　austenitic　stainless　steel,　uniaxial　tensile　tests　and　cyclic　loading　tests　of　round　bar　specimens　and　notched　specimens　for　S30408　austenitic　stainless　steel　were　carried　out　respectively.　In　terms　of　the　experimental　results　of　smooth　round　bars,　monotonic　and　cyclic　constitutive　models　of　austenitic　stainless　steel　530408　were　calibrated.　Furthermore,　the　parameters　of　stress　modified　critical　strain　(SMCS)　model,　void　growth　model　(VGM)　and　cyclic　void　growth　model　(CVGM)　were　calibrated　through　comparing　the　notched　round　bar　tests　with　the　corresponding　finite　element　analyses　(FEA).　Finally,　the　influence　of　element　size　on　the　fracture　prediction　of　the　micromechanical　models　was　analyzed.　Results　indicated　that　the　cyclic　hardening　responses　of　austenitic　stainless　steel　were　obvious.　Meanwhile,　the　calibrated　numerical　simulation　was　able　to　well　capture　the　key　characteristics　observed　in　the　tests.　In　addition,　as　for　VGM　and　SMCS　models,　the　fracture　prediction　values　increased　with　the　element　size.　Last　but　not　least,　in　terms　of　the　degraded　parameter　and　the　fracture　toughness　parameters,　it　was　proved　that　ULCF　fracture　resistance　of　austenitic　stainless　steel　was　better　than　common　structural　steels.　Therefore,　from　this　perspective,　austenitic　stainless　steel　structures　have　potential　advantages　to　be　applied　in　seismic　areas.