In this paper, a theory and application system, based on systematic engineering principals, about the stability studies of high rock slopes in complicated rock mechanics enviromental condidons is put forward. The main characteristics of this system is that the rock slopes are considered as a geological body firstly, then with the help of modern geological methods, modern mathematics and mechanics, and modern computer technology, their development and envolution courses which constitutes the main clue of this system, are investigated systematically and quantitatively so that the present stability states of rock slopes are ssessed and their stability changes on the future are forcasted.