Abstract: Based on the Chakrabarty's stretch membrane model, the relationship between the creep strain and the deflection was derived to calculate the experimental data from small punch creep test(SPC), and the relationship between the creep stress and the load was derived too. The Norton creep parameters of P91 material can be obtained from the experiments with nonlinear fitting. Then employed a finite element model of small punch creep test, a new method called inverse finite element was derived from comparison the second stage of experiments and simulations. The results show that the creep parameters of material can be obtained by small punch test. Based on tensile creep results, it is more convenient and accurately to get the creep parameters of P91 material by inverse finite element method.