The emergency situation caused by the abnormal service of an aeroengine, such as gradient loading, directly leads to blade rupture. Considering the effect of gradient loading on creep, a coupling creep model of nickel-based single crystals under gradient loading conditions is proposed based on crystal plastic theory and thermodynamic damage theory. Internal state variables—elastic strain, plastic strain and damage—are introduced to describe the thermodynamic irreversible process of a system. An anisotropic creep damage evolution equation represented by the damage strain energy release rate Y is deduced by the energy conversion method. The gradient loading creep behavior predicted by the finite element calculation is in good agreement with the experimental results.