The normal restitution coefficient of rockfall is the key parameter to determine the trajectory. The aim of the study is to reveal the influence of collision velocity and material parameters on the normal restitution coefficient of rockfall. The theoretical model of the rock sphere and the plate collision was established based on the elastic-plastic assumption. Furthermore, the collision between the rock sphere and the plate was simulated through the ABAQUS, and the velocity of the rock sphere was monitored in the collision process. The results show that numerical simulation and theoretical calculation are in good agreement, and the maximum difference is within 5%. The confining pressure causes the contact stress in the plastic zone to be greater than the elastic limit of the material. With the increase of collision velocity, the normal restitution coefficient of the rock sphere gradually decreases, and the decline rate gradually decreases. The normal restitution coefficient of the rock sphere decreases with the increase of elastic modulus and increases with the increase of elastic limit, which has a linear relationship. Poisson"s ratio has little effect on the normal restitution coefficient of the rock sphere.