Abstract: Theoretical analysis, numerical simulation and on-site observation were conduted to investigate the mechanical relationship between anchor rod/cable support and surrounding rock under mining stress conditions. PFC^3D discrete element numerical model of anchor/cable considering multi-level variable stiffness, consistent with the actual stress and deformation characteristics of anchor/cable, was established. The axial force distribution characteristics of prestressed anchor/cable of multi-level variable stiffness were analyzed, and the support characteristics of anchor/cable and the stress and fracture characteristics affected by mining were elucidated. Based on the particle motion characteristics and contact model characteristics of the discrete element bolt-cable, the stress and deformation characteristics of the engineering bolt-cable are simulated, and the variable stiffness function of the discrete element bolt-cable is realized by changing the parallel bond normal stiffness ( \bar k_n ) value in the tensile process. By introducing the stage critical coefficient as the threshold value of multi-level variable stiffness, the multi-level axial stiffness characteristics of single row particle anchor bolt (anchor cable) in the process of tension are realized. Different types of discrete element anchor bolt (anchor cable) models of multi-level variable stiffness are constructed, and their characteristic curves conform to the tensile characteristics of laboratory tests. The distribution characteristics of the axial force of the prestressed anchor cable in the surrounding rock of the three-dimensional roadway are obtained. The axial force of the free section remains basically unchanged in a cylindrical distribution, and the axial force of the anchoring section is conical, reaching the peak at the demarcation point. Under the action of mining stress, the axial force decreases firstly and then increases. The axial force of the bolt at the same position of the two sides shows asymmetric characteristics. The axial force of the bolt around the failed anchor cable is greater than that around the effective anchor cable. The axial force of the bolt/cable changes periodically, and shows tension, shear, bending and torsion deformation of the bolt/cable, which is in line with the fracture type of the anchor cable on site.