Abstract: This paper introduces the research development of rockfall trajectory and impact force in recent years. The development of rockfall risk assessment and prevention is also presented briefly in this paper. Field tests，model tests and numerical simulations are applied extensively in rockfall trajectory research nowadays, and numerical simulation has become the main research method. Three numerical simulation softwares: STONE, CRSP, RocFall are emphasized herein. Several rockfall impact force calculation methods are also enumerated in this paper. In future research, the transformation and combination of four types of rockfall motions, namely: sliding, free falling, bouncing and rolling should take into account in numerical simulation research on rockfall trajectory.