Dynamic grid deformation method with higher robustness is critical for unsteady flow problems which include moving boundaries. Two of rational and effective mesh quality parameters were introduced, namely Patrick parameters and Baker parameters. Then, a modified dynamic grid method was presented, which can optimize mesh quality on term of mesh quality feedback. Combined with large-pitching of 2D NACA0012 airfoil and 3D ONERA M6 wing, the difference between modified method and classical method was fully analyzed. Modified method has obvious advantage in mesh quality, and at the largest moving degree, it can significantly enhance the robustness of grid mainly through perfecting the worse element. Finally, the modified method was applied to simulate the pitching motion of NACA0012 airfoil and ONERA M6 wing, and the calculations were compared with the experimental values and literature. Result shows that the modified method can improve stronger robustness, therefore it can provide better support for unsteady flow problems.