The microstructures and properties of (Tb,Sm)CoSi/Cr series films have been investigated. All the samples were sputtered and annealed at 500 °C for 25 min in pure N2 atmosphere, and their microstructures and properties were examined. The effect on the magnetic properties of partial Sm substituted by Tb is discussed. The lattice matching media were examined. And the mechanisms of interactions among the grains and between the magnetic layers have been analyzed by comparing multi magnetic layer with the mono magnetic layer.