The finite element analysis is used to predict the bending capacity and failure mechanism of composite hat-stiffened panel with pre-filled blocks， and the experiment verification is completed. Firstly， based on the finite element software ABAQUS， a solid finite element analysis model of hat-stiffened panel with pre-filled blocks is established， and cohesive zone model is used to simulate the interface between the rib and skin. At the same time， based on the Hashin and Tsai-Wu criteria， the user-defined material subroutine （UMAT） is written. The results show that load capacity，damage mechanism and failure location of the finite element simulation are consistent with the results of the experiment， and the load-displacement curve is roughly the same. When the ultimate load is reached， the rib fails at the junction of the chopped fiber block and the foam in the form of “compression”， resulting in a decrease in the structural load-bearing capacity. There is no debonding phenomenon between the ribs and the skin in the experiment and simulation. Moreover， increasing the number of rib layers and the length of chopped fiber blocks can effectively improve the structural load-bearing capacity.