Abstract: A three-dimensional (3D) nonlinear progressive damage analysis (PDA) model at the mesoscale level was presented in order to take into account the interlaminar stress and damaged material nonlinearity. The typical PDA consists of stress analysis，material failure initiation criteria and damaged material degradation rules. Adamaged material degradation rule was discussed mainly to introduce damage status invariables corresponding to different damage modes. The material stiffness matrix at each material point was degraded directly through damage status invariables. The proposed model can predict composites laminates damage initiation，progression until final failure and ultimate strength. 12  laminates with different stacking designs were analyzed with the model. The good agreement between the predicted ultimate strength and the experiments shows correctness of the model for laminates ultimate strength prediction.