The permeable agent, process parameters, microstructure and properties after co-osmosis and its application in mold were studied. Solid boron nitriding agent is composed of boron supplier, nitrogen supply, activator and filler, which is simple in process and easy to implement, and is a chemical heat treatment method that can obtain good permeable layer performance. Through solid boron nitriding to obtain a reliable and stable boron nitriding layer on the mold surface, the permeable layer is composed of boride layer (Fe2B, FeB) and transition layer, and a boride layer with high hardness can be obtained after infiltration, and the permeable layer has high wear resistance, good heat resistance and corrosion resistance. The application of boron nitriding technology in the manufacture of molds can greatly improve the service life of molds.