This paper proposes a method of inelastic structural analysis for YH61 nickel base single crystal superalloy. Hill's anisotropic constitutive equation was applied to describe the elastic-plastic deformation of the superalloy. The equation well described the static tensile curves of the solid bar specimen with <100> and <110> axes at 1173K. The equation also well expressed the torsion curves of hollow cylinder specimens with <100> axis at 1173K. The Hill's equation was applied to simulate the creep deformation of the superalloy. The equation gave satisfactory results for predicting the creep deformation of solid bars having <100> and <110> axes. The Hill's equation was used to predict the creep-fatigue deformation of a cruciform specimen in biaxial loading, resulting in a good agreement with the experimental deformation.
