We have proposed a new creep constitutive equation of Ni-base superalloys with good reproductibility and predictivity under the conditions of high temperature-low stress and intermediate temperature-intermediate stress. In this paper, an application of the creep constitutive equation for low temperature-high stress condition (800°C/735 MPa) is discussed. It is said that at low temperature-high stress condition, a Ni-base superalloy has different deformation mechanism from the condition of higher temperature-lower stress. A good reproducivility for each creep curve with applying the creep constitutive equation has achieved. Although this good reproducivility, the result of multi regression analysis for each parameter of the creep constitutive equation with composition and strucutural parameters point out that it is different tendency from higher temperature-lower stress conditions.