The　deformation　distribution　and　the　load-deflection　characteristic　of　high-strength　steel　fiber　reinforced　concrete　square　slab　subjected　to　punching　shear　were　obtained　experimentally.　It　is　assumed　that　the　deformation　of　slab　before　punching　shear　failure　is　primarily　caused　by　bending　moment.　The　deformation　not　only　reflects　the　flexure　behavior　of　slab　at　every　loading　stage,　but　also　affects　the　stress　status　on　the　surface　of　punching　shear　cone　and　the　ultimate　capacity　of　the　slab.　In　this　paper,　the　deformations　of　punching　shear　slabs　at　three　loading　stages　before　failure　are　calculated.　Good　agreement　between　the　theoretical　values　and　the　testing　curves　is　reached.