To research the unfolding performance in order to ensure the grid fins used on trajectory correction fuze working reliable. First, the equation of unfolding base on Newton's Second Law of Motion-Force and Accelerate was established, which provided a theoretic base for the simulation. Then calculate the aerodynamic force which wing suffers in the unfolding in flight. To calculate the stiffness of torsional spring the equation established was used. Next, the data such as impact and stress of the grid fins was calculated through ADAMS. Finally, the strength check analysis was made. The results show that the unfolding time could meet the need, it can unfold to specified position and lock up quickly. Besides, the strength of the material meets the requirement. The results of research can support the structural design and optimizing.