To research the approach of predicting composites fatigue life, the cumulative fatigue damage of fi-ber-reinforced plastic laminates(FRP) was investigated, and based on the complex exponential function, the residual strength model was obtained. This model can accurately describe the propagation of cumulative fatigue damage of FRP in three stages, especially in the initial stage and the ceasing stage. Applying this model in the experiment with two loading cycles, it can be found that the prediction result has good coincidence with experimental data. So a rehable residual strength model can be provided for studying the cumulative fatigue damage of FRP.