In Japan，the mountain region are formed of steep topography，the fragility of this region can be attribute to the unstable crust structure and the volcanic activities. The location of the country in typhoon and earthquake zones increases the possibility of natural disasters，especially because 2/3 of the country's area is full with mountains. In June 29，1999，a heavy rain occurred in Hiroshima. The rain made serious slides in the mountain areas. This study presents afield survey and soil testing in Yashiro，Kannon and kamikobukawa areas, where the heavy rain disaster occurred. Slope stability is applied to the slope which collapsed. Based on the results. The method of slices is introduced and the safety is examined in consideration of soil data