Abstract: Abstract：Response to the reasonable supporting of the open-off cut with large cross-section, based on the 122106 open-off cut in Caojiatan coal mine, this paper studies the loading and deformation characteristics of the roadway in the conditions of different roof span through theoretical analysis and discrete element numerical simulation. A high strength, high pre-tightening force and low density spanning reduction support technology, such as "secondary roadway + single hydraulic prop + high-strength Anchor Mesh Cable + W steel shield", has been proposed to support the large section coal roadway. Consequently, support efficiency has been improved and then the roadway driving speed has been accelerated significantly. The research shows that when the roof span exceeds 9m, the stability of the roof decreases dramatically, and the phenomenon of surface coal failure and collapse is easy to occur; the bearing capacity of the bolt is closely related to the pre-tightening force, and the larger the pre-tightening force, the better the bearing capacity of the bolt is; research results are verified by field measurement. The roadway did not appear obvious deformation, and the supporting body remain stable under loading.