Abstract: This paper presents the experimental study for the physical-mechanical-chemical behaviour of the mud stone for one open pit coal mine. The experimental results indicate that large amount water affinity and colloid material are contained in the mud stone. It is find out that the mud stone under investigation has loose structure and high degree of saturation. The relation between the number of dynamical loading cycle and the strength, deformation of mud stone. It is find out that the mud stone under investigation has loose structure and high degree of saturation. The relation between the number of dynamical loading cycle and the strength, deformation of mud stone is obtained through the dynamical triaxiali shear tests. The failure mechanism under different confine stress and the relation between the moisture content and the strength of the mud stone are also investigated. Finally, the displacement under wheel points and the deformation and non-homogenous road base under different loading by finit element analysis are given in this paper.