Conjugate cam beating-up mechanism is widely used in high-speed rapier loom. The research of its dynamic characteristic is beneficial to improve the mechanical properties of looms and enhance the production efficiency. The flexible component of the beating-up mechanism is discretized based on the finite element method. It serves as the physical model foundation for obtaining accurate dynamics model. Furthermore,the dynamic model of the beating-up mechanism is calculated by Kane’s equations and modal synthesis technique. The obtained dynamic equation is not only in a simple form,but also efficiently computable. Based on this dynamic model,the simulation of the influence of cam rotation speed,beating up resistance and structure parameters to dynamic response are proposed. The results show that the mechanism deformation from the rotation speed increases and the beating up resistance is not big enough to affect its performance,while the variation of the rotation speed affects the mechanism acceleration obviously. Research results will provide a basis for improving dynamic performance in different working conditions and with various structure parameters,furthermore,research results can laid a theoretical basis for more precise dynamic optimization design of high-speed beating-up mechanism.