Abstract: The 5203 open-off cut of one coal mine in Shanxi province was taken as the project background. The variation characteristics of vertical stress, horizontal stress, tension and shear plastic zone, displacement after once, twice excavation were described. The design idea of taking shoulder angle stability zone as the anchor base and combination support technology of bolt, truss and anchor rope were put forward. The success of industrial test proves that the guiding ideology and support technology are suitable to the large section open-off cut.