The coefficient of restitution (COR) is one of the important mechanical properties of particle. The calculation model of the energetic COR of particle-particle collisions was derived. The method used to determine the energetic COR of irregular particles was proposed. Maize particle-particle collisions were simulated using the discrete element method (DEM). The kinetic energy of the particles during the collision was investigated. The relationship between the input and calculated energetic COR was obtained via simulation. The energetic COR of maize grain was obtained and verified using laboratory experiments. The results indicate that it is accurate. The results of the simulation indicate that the energetic COR is more accurate than the kinematic COR for maize grain. The effects of the impact velocity and impact angle on the energetic COR were investigated. The results of the paper will be helpful for maize grain simulation and maize-processing machine design. (C) 2019 Elsevier B.V. All rights reserved.