Abstract: To solve the problem of large deformation and even roof caving in soft and weak thick coal seam roof support with large span cutting hole, take 20102 open-off cut as a research object, using numerical simulation and theoretical analysis, it is revealed that the point column can decrease the span of roof, decrease the depth of roof crack cut-through area and lower arch height, which is beneficial to the reinforcement of surrounding rock with anchor and the suspension of anchor cable, and can effectively control the deformation of roof with large span. Based on this, the failure mechanism of large span open-off roof was revealed, and the combined roof control technology of “temporary point column + common anchor cable net + steel ladder beam” was successfully applied to effectively control the large deformation of roof.