Stitched woven composite π joints and paralleled samples without stitching were investigated by numerical analysis under tensile loading. The effects of stitching on the mechanics behavior of composite π joints are presented. Stitching technique can reduce initial failure load of composite π joint, but remarkably improve the rupture load. The failure process of composite π joint, including the damage onset, propagation path and final failure pattern, is also limited in the stitched area. The failure mechanisms are expatiated by the numerical data and failure picture to obtain more knowledge about the mechanics behavior of composite π joints.