Abstract: In view of the stability problem of side slope in construction of Tibet Bangpu Open-pit Mine, the field measurement on the structure plane in tunnel of mining area was firstly made. And the roses diagram, the isodensity map and the perspective projection drawings were got through the statistical analysis of the occurrence of structure plane; Then, combing with the characteristics of landforms, geological structure and the structure plane of side slope in openpit mine, the preferred structure plane which control the stability of side slope was attained-Lastly, the qualitative analysis on the stability of side slope was made by the stereographic projection.

Key words: Structure plane statistics, Preferred structure plane, Stereographic projection, Slope stability