DFT-based spin-polarized simulations are performed with van der Waals (vdW) interaction included and in combination with STM and LEED experiments to study adsorption and reconstruction, and their relations with molecular spin-polarization and magnetoresistance (MR) enhancement, for typical molecules on various types of magnetic surfaces.Recent studies show that molecular adsorption can induce reconstruction of close-packed metal surfaces, such as the reconstructions of Cu, Au and Pt surfaces with adsorption of fullerene, thiolate and graphene;these studies focused on nonmagnetic electrodes and are of great importance for molecular electronics studies.Our studies extend adsorption induced surface reconstruction to molecular spintronics viadetailed study of the interaction of molecules with ferromagnetic and antiferromagnetic metals, etc.Our studies show that magnetic surface reconstruction induced by molecular adsorption can enhance the spin-dependent hybridization at molecule-electrode interface, which makes simultaneously increase MR and conductance possible, and increase these two parameters simultaneously are essential for further miniaturization of spintronic devices.In addition, vdW interactions are very important for the determination of interface bonding mechanism and hence important for the determination of magnetic properties.