The dynamic model for links in most mechanisms has often based on small deflection theory without considering geometrical nonlinearity. For applications like light-weight links or high-precision elements, it is necessary to capture the large deflection caused by bending forces. A complete dynamic model is presented here to characterize the motion of a compliant mechanism capable of large deflection with shear and axial deformation. We derive the governing equations from Hamilton's principle along with the essential geometric constraints that relate deformation and coordinate variables, and solve them using a semi-discrete method based on the Newmark scheme and shooting method. The dynamic model has been validated experimentally. We also extend the model for analyzing compliant mechanisms. It is expected that the dynamic model will serve as a basis for analyzing a wide spectrum of compliant multi-link mechanisms.