Abstract: Scheidegger’s Antagonism Principle about two types of process active in the formation of Earth’s surface landforms is a fundamental principle of landscape evolution. The two processes have a basic different stochastic nature, endogenic processes are essentially systematic(non-random)and exogenic ones essentially random. The genesis of orientation structure of river valley along which highway is mostly built has tranditionally been ascribed solely to exogenic, nontectonic causes. The orienta-tion is not random indeed but corresponds to the shear lines of a neotectonic stress field in an area. Road can be regarded as a kind of artificial landscape on which the neotectonic stress field has an effect in same way. If direction of a road is parallel with shear lines or perpendicular to principle press stress of a neotectonic stress field, its stability will go bad specially in a high geostress area. Investigation on the failure and washout disarsters, of roads in South Gansu Province and West Sichuan Province has proved this hypothesis.The water destruction of road being similar to destruction of a navigation channel or road tunnel is a kind of natural disas-ter of the man-earth system which is a behavior in the critical state of complex system and should be researched by the ap-proaches of nonlinear dynamics or complexity thoery from the Man-Earth Synergetics.