Abstract: Based on the exploration data of engineering geology, and by means of geological method and the analysis of mathematical statistics of test parameters, polus morphism project figures as well as the analysis of a typical engineering case, the main characteristics of the rock types and the factors affecting the stability of the tunnel wall rocks are studied, which makes a conclusion that the collapse is the major engineering geology problem in the tunnel engineering and that the development of the schistosity in the vein body fringe and cracks and precipitation significantly affect the stability of tunnel wall rocks.