Abstract: The mechanical responses of stiffened composite plates with a notch under compression were investigated by experiment and FEA method with a progressive failure procedure. The damage propagation and failure property of a stiffened panel reinforced by stitch with discrete-source had been studied. The results indicated that at the tip of the notch there was high stress concentration and damage occurred firstly. The buckling and collapse of the intact ribs in the direction of the notch and the edges of plate resulted in ultimate failure of the stiffened plate. The FEA method with progressive failure procedure based on Maximum Strain Criterion and Hashin Criterion simulated the notched stiffened composite panels’ damage evolution effectively. The analytical results were in good agreement with the experimental data.