Abstract: The bending and toppling deformation in slopes of mica quartz schist occurs due to shear displacement slice by slice of schist with concentrated schistosities. The paper gives a theoretical formula of angle between 1and the normal to schistosity plane when the instantaneous deformation is finished. Since then, shear-creep will take place along the schistosities by the shearing stress acting on the plane. The formula of -t is given in the paper. At last, the effect of groundwater pressure on the bending and toppling deformation is also discussed and considered in the theoretical formulas.