Abstract：As human activities(especially engineering activities) increase in quantities and scopes，geological hazards resulted from landslides or underground collapses are even more frequent. For this reason，preventions and reductions of the geological hazards also become very important and necessary. It is indicated in many studies that those hazards are often closely related with geological structural planes. Therefore，geometrical conditions of the structural planes and blocks resulted from the combination and intersection of the structural planes and free surfaces should be carefully considered for the investigation into modes，scales and countermeasures of landslides or underground collapses. To describe those blocks and analyze their stabilities，the stereographic projection diagram method is developed and employed. This method is characterized by a better combination of engineering geological conditions and block stability analysis；however，it has difficulties in solving multiple blocks and lower efficiency in diagrammatic process. According to the former shortage，the coordination projection mapping method(CPMM) is given. To increase diagramming efficiency，the computer procedures based on the CPMMs are programmed. It is expected that the presented diagram method will become a new technique for prediction and prevention of landslides or collapses.
