The size, sliding direction and catastrophe of the Upper Permian Emeishan basalt landslides in eastern Yunnan fold zone of Yangtze paraplatform is not stochastic but being constrained by the geological settings in this area. The Himalayan movement made the paraplatform cover sandwiching Emeishan basalt rise and being folded. The dip state of the Emeishan basalt layers which are interbedded in the monoclinal blocks and fold limbs makes the basis for their slide along the bedding plane. The tectonic lines in eastern Yunnan fold zone are relatively sparse and the higher integrality of the Emeishan basalt is of importance for the basalt massive sliding failure. The strikes of the faults and folds which regulate the attitude of the Emeishan basalt are mainly northeast direction, and thus the direction of the basalt sliding failures is southeast or northwest. Valleys cut by the trunk steams which develop along the faults and folds with northeast strike provide the Emeishan basalt failure with base levels. The branches are in general perpendicular to their trunk streams and their head erosions strip the overlying strata of the dip Emeishan basalt layers and provide the basalt landslides with migration pathways and depositing sites. Tremendous casualties given rise to by the Emeishan basalt landslides have relationship not only with reticulate negative relief cut by the above river system and it's northwest tributary, but also with formation character of the overlying strata of the Emeishan basalt. There is a higher population density in the valleys of northeast rivers, especially in the cross positions with their tributaries. The overlying strata of the Emeishan basalt that has being cut by the northwest tributaries is continental sedimentary rock formation and tends to weather into soil. There is a greet extent of land development or vegetation cover in the mountains between different tributaries. The need for land, woodland and water resources make the northwest tributary valleys with a high population density. Thus, the population distribution is intensive in potential pass ways and deposit sites of the Emeishan basalt landslides. It is obvious that once the basalt landslides occur, maybe the results are catastrophic.