Using survey grid method the structural plane in rocky slope alongside the Qingyuan-Lianzhou Highway in Guangdong province are measured. The survey parameters are counted and analyzed by thr ＂structural equator proiection data analysis package＂, and simulated by the 2-D network simulation program. Based on this works the characteristics and combination relationship of the structural planes, as well as their influence on the slopes’stability, are researched. The result shows that the influence of the combination relationship on the slopes＂ stability is obvious.