Abstract: Considering the location charactor of railway direction,from geological aspect the system summarizes and generaliaed major problems(landslide ,mud-rock flow,desert,karst)affecting the location of railway direction,and set up a knowledge-base and inference scheme.This system may provide information on location of a railway direction,so as to reduce the blunders,save the cost and accomplish punctually the railway construction.In this paper the authors centre on introducing the composition of this system and concrete design method and design technique of every compositing part.