Directional solidification and single crystal technology reduces material defects, improves material mechanical property and improves resistances to the high temperature fatigue, creep and corrosion. Accumulation of fatigue damage is a method of life prediction analysis and many fatigue damage models are proposed. Based on foregone research achievements, this paper presents a fatigue damage model, which could reflect material anisotropy and thermomechanical coupling effect. Based on equivalent strain, a fatigue damage evaluation method of directionally solidified and single crystal superalloy is presented and by this method, the linear fit of published fatigue experiment data is proceeded. Directionally solidified and single crystal superalloy is of strong anisotropy and crystal orientation has strong effect on component mechanical response. Comparative life of different location on component could be analyzed.