This study delves into the dynamic characteristics of ripples in two-dimensional (2D) nanofilms considering scale effects through nonlocal theory and molecular dynamics simulations. Initially, ripple dynamics model for 2D nanofilms under terahertz (THz) excitation is constructed based on the nonlocal Kirchhoff plate theory, revealing the relationship between ripple wavenumber and THz excitation frequency. Subsequently, the accuracy of the nonlocal ripple dynamics model is verified by comparing it with molecular dynamics simulations, and the nonlocal parameters is identified. Furthermore, the differences between the discrete molecular dynamics model and the continuous medium theory model for 2D film structures at small scales is analyzed, and the effects of important parameters such as equivalent thickness, chirality and nonlocal parameters on ripple wavenumber and phase velocity is discussed. The study indicates that when the ripple wavelength approaches the scale of carbon-carbon bonds, the discrete nature of atoms disrupts the uniformity of adjacent ripples, demonstrating the importance of considering the discrete nature of atomic distribution for modeling the cross-scale ripple dynamics of 2D nanofilms under high-frequency THz excitation. Additionally, it is found that the phase velocity in the zigzag direction is greater than that in the armchair direction, and as the central excitation frequency increases, the wave pattern of closed ripples transitions from circular to hexagonal.