In this paper, a refined model of interlocked composite gird stiffened structure and an equivalent model based on simplified ICG panel are built. Buckling and dynamic response of the composite panel are then analyzed using the models. The result is the accuracy of buckling and mode analysis of refined model is greatly improved compared with the equivalent model. Simulation for impact response under different impactors is considered. The coefficients such as material properties and structure dimension of the slot are discussed.