The spring analogy method, based on the physical model, and the radial basis functions (RBFs) interpolation method, based on the algebraic method are two typical and common unstructured grid deformation methods to achieve the computing grid deformed with the moved boundary in unsteady flow simulation. In this paper, a detailed quantitative study is conducted on the deformation characteristics of the two methods. First of all, the pitching of NACA0012 airfoil is taken as an example to compare the CPU time and the maximum deformation capacity of the two methods. Furthermore, the mesh quality and cell quality contours under typical pitch angles change with pitching angles and time steps are also studied. A standard flow solver result is proposed as well. The above results show that the RBFs method is remarked with higher numerical efficiency, stronger adapting ability for large mesh deformation and higher stability for mesh quality comparing with the spring analogy method .