In order to study the properties of stiffened composite panels (T300/BA9913) which were intended to use for a type of UAV, it carried out the impact damage. The primary details is : Impact in the middle of the wall plate and the joint of rib and wall plate, the impact energy is 6.67 J/mm, measuring the impact indentation depth and delamination damage area.; This paper applies the commercial software ABAQUS and writes the corresponding VUMAT subroutine to simulate the impact damage. The strain-based 3D Hashin criterion was applied to the damage criterion of composite single-layer panels by using the suitable material model, the type of unit and the contact with different attributes in the software. The comparison of stiffness reduction of materials based on continuous stiffness degradation principle of fracture toughness and impact test data verified the validity and accuracy of the established impact model.