Abstract: The creep tests on the Cr25Ni35Nb furnace tube steel were performed under different temperatures and stresses, the creep curves for the steel were fitted by modified θ projection method. The mathematical expressions of the parameter θi were built and the creep curve equation of the steel under arbitrary temperatures and stresses was established. Then the creep curve at 950 ℃ and 18 MPa was predicted. The results indicate that the predicted creep curve showed a good agreement with the experimental one.