Geological environment is an important factor to be researched in geological engineering. It not only relates to the successes or not of engineering actives by human，but also makes influences on the relation between geological environment and engineering itself in the period of use after completion of construction. Especially when the evaluation is made for the stability of engineering site，the geological environment factors are very important. The geological environment factors include geological structure (soft intercalated bed and soft structural plane)，living fault, crustal stress, ground water and surface water. On the basis of analysis of the causes for distortion and instability of Jinchuan side slope，this paper puts forward main factors for control of side slope distortion , namely high crustal stress，soft intercalated plane and surface water, and describes the role of geological environment factors in engineering actives.