Abstract: A three dimensional interfacial fatigue damage model was proposed. Mixed mode delamination of laminated composites caused by both monotonic and fatigue loads can be represented by this model. The maximum jumping displacement of interface experienced in the history was adopted as the damage indicator. For fatigue load，damage accumulation in one unloading and reloading cycle was taken into account. Damage thresholds and nointerface interpenetration conditions were considered in this model. A three-dimensional eight-node isoparametric interfacial element without initial thickness was constructed to model the constitutive law of the interface. A damage accelerating arithmetic was introduced to reduce the computing time. In this arithmetic damage accumulation in several real loading cycles was represented by damage increment in one computing cycle. This element was used to simulate the initiation and growth of fatigue delamination in a laminated composite rotating component . The interfacial damage near the interface crack tip and the development of delamination in the component were obtained. The predicted a-log N curves and residual stiffness agree well with the experimental data.