Based on a field research on the Open-pit Mine and a series of outcrop and lab experiments

the engineering geological conditions such as the lithotype distributing character of rock masses on the northern-side of the mine

and the developing state of faults and joints

are analyzed. Considering that the mine is a slope-type open-pit mine and in consideration of the feature of local crustal stress

a typical section is chosen; and an elastoplastic mechanical model is established; and Drucker-Prager criterion is adopted. According to elastoplastic mechanical model

the influential degree of blasting shock on stability of the high-steep rock slope in mountain area is imitated by using elastoplastic finite elements method

the displacement field and the safety factor of the slope with fault at later stage are computed. Finally

the whole stability of the slope in later period is explored and some useful countermeasures are put forward.