A cavitation degradation process and fatigue phenomenon were described. Similarly to fatigue phenomenon, cavitation pulses division into three fractions was suggested. The action of each fraction was respectively compared to low-cycle fatigue, high-cycle fatigue and low-amplitude fatigue. The action of each fraction was described separately. Detailed analysis of the influence of each fraction on the degradation process shows that besides mechanical loading also thermal loading occurs. The cavitation erosion is assumed to be the sum of degradation of each fraction. Thus, the model of PVD coatings degradation under action of cavitation pulses include variable-amplitude and variable-temperature fatigue.