The invention discloses a preparing method for a CuW/Al bimetallic material of a porous structure blocking layer. A nickel diffusion impervious layer is prepared on the surface of preprocessed CuW alloy; the surface of an aluminum block is cleaned so that the surface of the aluminum block can be smooth, clean and free of oxide, and then the aluminum block is for standby use; after the aluminum block and the CuW alloy with the nickel diffusion impervious layer are welded, the CuW/Al bimetallic material is obtained. According to the preparing method, the surface of the CuW alloy is preprocessed so that a W framework with the height of 100-200 microns can be formed on the surface of the CuW alloy, and the nickel diffusion impervious layer is added to the W framework; on one hand, the combining area of aluminum and the nickel diffusion impervious layer is increased, and the bonding strength of an interface is easily improved; on the other hand, a solid solution is formed merely through mutual diffusion of elements of Ni, Al and W, generation of a friable intermetallic compound Al2Cu in the CuW/Al interface diffusion impervious layer is effectively inhibited, and the interface controllability is improved.