Asteroid exploration will be the spotlight of the research in aerospace science in upcoming decade. The present data indicates that most of the asteroids are loosely consolidated "rubble pile" structures, which have zero tensile strength and are easy to be disrupted by external force produced by exploration missions. Therefore, to guarantee the execution of the asteroid exploration mission, it is essential to build the dynamics model of the asteroid and explore the asteroid evolution's interaction effect. Based on the upcoming China's asteroid exploration mission, the research status and development of granular dynamics is reviewed and analyzed. Then, the dynamical modeling and numerical simulation methods of rubble-pile asteroids are recapitulated in detail, according to the state of art of international relating researches. Finally, the key technical problems of the modeling of rubble-pile asteroids in asteroid exploration mission are proposed.