Supplementary Information for ``Multiferroic properties and the layer-stacking quantum anomalous Hall effect in two-dimensional RuOHX (X=F, Cl, Br)"

Analysis of valley polarization by SOC Hamiltonian, information on the geometry structure, stability, magnetism, topological properties of monolayers, geometry structures and band structures of all stacking bilyers, Berry curvatures, WCCs, SHC and edge states under different circumstances.