Abstract: Loess landslide is the main factor which influences the infrastructure construction such as highway,railway and so on.In certain extent,the formation of the loess landslide is the deformation and destruction of sliding soil.The paper made a systemic study including the classification,physical and mechanical properties,the microcosmic and macroscopic properties of the sliding soil.And the deformation and destruction of sliding soil mechanism are explored.At last,the loess landslide case of Tianshui,Gansu Province was analysed.