The strength parameters of a typical remolded expansion rock of different water contents and dry weight densities, as well as in wetting and drying cycles state in some region of Xinjiang were studied by directing shear experiment. The research indicated that with the increase of moisture content, the strength parameters of expansion rock increase at first and decrease subsequently, and there is the best moisture content of cohesion and angle of internal friction to get the maximum of strength. In case of the same water content, with the increase of dry weight density, the cohesion of expansion rock increases, but the angle of internal friction changes little. With the increase of the wetting and drying cycles, the strength of expansion rock decreases, but after a certain number, the strength parameter doesn't decline obviously and finally stabilize gradually.