Abstract: The difference in properties and stress states of soils in each section of a broken-line complex landslide exacerbates the difficulty of judging its stability. Taking this kind of landslide as the object, the mechanical discrimination of evolution of stability state of progressive failure is studied. Considering the strain-softening characteristics of soils in sliding zone, the mechanical model for the landslide is established, and its progressive failure process is divided into eight evolutionary stages. According to the static equilibrium principle and the transfer coefficient method, the relevant equation for calculating stability of each stage of the landslide is established. The load transfer mechanism between the front and rear to the middle section in the progressive development of the landslide is shown, and the quantitative difference and evolution law of the loads, stress distribution and stability states between the part and the whole of the landslide are revealed. The results show that the stability of the landslide decreases slightly at the initial stage of evolution, and when the progressive failure develops to the middle locking section, the it begins to decline greatly. The control projects laid at the front and rear before the self-imposed load stage of the landslide are energy-saving and efficient. If it is at this stage, the control position should be determined by combining the position of the equivalent load transfer and the accumulation of the self-imposed loads, and the stability of locking section should be considered when missing the key stage of control.