The deep screening of wet fine coal can be effectively solved by the flip-flow screen, and the motion of screen panel has important effects on the depolymerization of wet fine coal mass. In order to study the depolymerization mechanism of wet fine coal mass in the process of large deflection elastic collision. In this paper, a kinematic simulation model of large deflection elastic screen panel is established based on Bonding Particle Model in discrete element method. Through the use of contact models after redevelopment, the large particle coal is replaced by the agglomerated equal diameter fine particle coal. The elastic collision between wet fine coal mass and large deflection screen panel is simulated and analyzed, and the influence of screen surface amplitude, frequency and collision velocity between fine coal mass and elastic screen surface on the depolymerization of fine coal mass was studied. Results show that the depolymerization degree of fine coal mass increases with the increase of the amplitude and frequency of the screen panel, and increases firstly and then decreases with the increase of the collision velocity between the coal mass and the screen panel, and the number of collisions increases with the increase of the frequency. This research is beneficial for the application of the discrete element method in the process of elastic screening with large deflection.