Abstract: Compare with slope collapse and landside,rockfall is only a kind of small scaled geological hazards.But it always occurs suddenly and hard to be forecasted,which can damage structures,transportation infrastructures and threaten human lives.Rockfalls happened widely in Wenchuan earthquake,which has brought about more attentions on this kind of hazards.Based on engineering practice,both the kinematics with probability and statistics and empirical formulae were used in calculating the velocity and kinetic energy of rockfall.Velocity and kinetic energy of rock blocks that may run along the high slopes are calculated when they arrive the location where a structure is planed to be built.The results of these two methods were analyzed.Only single values can be gained by empirical formulae while values in distribution can be calculated by the kinematics with probability and statistics for one slope.The result of velocity of the former method locates in the rage of bigger values in the results distribution of the latter method,which is in a rather safe rage.As the rotational kinetic energy is estimated smaller by empirical formulae than the kinematics with probability and statistics,the total kinetic energy is smaller accordingly by empirical formulae.By the above results and analyses,it is recommended to relocate the structure so as to prevent from being damaged in future rockfall that may happen.