The traditional LCF life prediction methods based on the macroscopic level cannot accurately describe the microscopic fatigue failure behavior of materials. Few studies investigate the effects of different strain ratios on LCF life prediction at constant maximum strain. Therefore, the crystal plasticity finite element method and representative volume elements are employed to examine the LCF behavior of nickel-based superalloy FGH4098 with different strain ratios at constant maximum strain. The parameter based on energy is also utilized to predict its LCF life. In addition, the applicability of the material's constitutive parameters under different strain ratios is analyzed. The results show that the use of specific constitutive parameters for different strain amplitudes significantly improves life prediction accuracy.