Abstract: Through the punching shear experiments of 6 blocks of steel fiber reinforced high-strength concrete square slabs with the size of 1 800mm @ 1 800mm@ 150mm, the effect of the concrete intensity and the steel fiber volume on the loaddeflection curve are investigated. The results indicate that the deformation of a slab prior to punching shear failure is mainly bending deformation and the mixture of steel fiber hightens the first crack load, rigidity, ductility and limit bearing capacity of reinforced concrete slab. Based on the experiment results, it is introduced the reduction coefficient of rigidity to inflect the effect of steel fiber on deflection varation and it is set up the related formula of load and deflection which is applied to the whole process from loading to destructing.