Abstract: The rectifying properties of La_0.8Sr_0.2MnO₃（LSMO）/Si with SrMnO₃（SMO） as barrier layer were compared with the one without SMO,prepared by using RF magnetron sputtering on Silicon substrate.The X-ray diffraction was used to study the structures of the films and the reason of preferential orientation of the films was investigated subsequently.RBS measurement shows the interdiffusion between LSMO and Si is dramatically impaired through introducing SMO barrier layer.Consequently,the rectifying properties of LSMO/SMO/Si is improved compared with LSMO/Si obviously.But thicker intermediate layer results in the weakening of rectifying properties.