Abstract: The electromagnetic wave reflectivity and transmissivity of plain concrete, steel wire mesh and steel wire mesh concrete were numerically studied. Firstly, model simulation results were compared with experimental data of reflectivity and transmissivity and the discrepancy was analyzed. Secondly, two different steel wire meshes were simulated and compared with experimental results, and parameters including wire diameter, mesh diameter and number of layers were studied. Lastly, the steel wires and the influence of their positions on the reflectivity and transmissivity were studied. In this paper, a numerical simulation tool Ansoft HFSS 15.0 was used. When the diameters of steel wires are the same, the larger the mesh diameter is, the lower the reflectivity is. Joining steel wires has little effect on the average reflectivity of concrete, but could affect the harmonicity of the reflectivity curve.