created numerous rock mass discontinuities in this area, which exist in many forms such as fissures,cleavages, beddings, joints, and even faults. In past decades, rockfall hazards triggered by earthquake activity and heavy rainfall have frequently occurred in Taiwan, especially after the 921 earthquake in 1999 and Typhoon Morakat in 2009. Considerable rockfall hazards have increased dramatically and become a major obstacle for engineers. This study develops a 3-D numerical rockfall model based on the lumped mass method which treats the falling block as a point mass and allows mass free fall, impact and rolling motions in a 3-D framework. It is hoped that the 3-D rockfall analysis program can be useful for analyzing regional scale rockfall problems as well as for delineating areas of rockfall susceptibility.