Abstract: The landslides of opencast mines, the surrounding rock instability of underground opening and surface collapse are the three main geologic hazardr or geotechnique problems of mines. From the view point of preferred plane analysis they are controlled by preferred faults or planes, and the effective research methodologies are the combination of expert judgement, mechanism analysis and quantitative model. The fundamental theorem of preferred plane for the hazards evaluation which are now recongnized as imposing a primary control of the origin, evalution assessment and prevention of the three hazards are also introduced in this paper. They are:(1)System analysis;(2)Analysis by the combination of inner and outer forces; (3)The view point of two mechanisms; (4)Analysis of extent of harm and decision; (5)The view point of preferred plane for hazards reaction and prevention.