Quantifying the relationship between faulting and the spatial geometrical and mechanical characteristics of a rock mass controlled by faulting is difficult, mainly because of varying lithology and rock mass characteristics, the effects of topography and vegetation and local erosion of weaker rock mass. In this study, the procedures, investigation approaches, evidence and criteria for defining the threshold distance for damage zones of Yarlung Tsangpo (YLTP) Fault of southern Tibet were studied quantitatively by combining the spatial variations of fracture density, rock mass strength, rockfall inventory and previous thermal evidence. The extent of threshold distance of damage zone of the YLTP Fault is estimated at 5.9±0.6km. The internal dynamic action of fault controls rock mass physical and mechanical properties in the study area. The fault first affects the characteristics of rock mass structures, and then the orientation of the rock structures influences the stability of slope leading to rockfall.