Abstract: The load transfer mechanisms at the post-buckling stage were studied for an integrated stiffened composite panel subjected to uniaxial compression. An FEM model was created for the panel by using the commercial software ABAQUS. The post-buckling process of the panel was simulated under uniaxial compression. The internal resultant forces and the load transfer mechanisms were discussed in detail at different stages (i.e., the local and global post-buckling). The distributions for resultant forces and moments at nodal and anti-nodal lines were obtained. The simulations agree well with experimental data. Finally it is indicated that the nodal and anti-nodal lines are possibly the first debonding locations of the flange/skin interface at the post-buckling stage and the forces crucial for failure are identified as M_xy和M_y.