The present invention discloses a selectively passing material and a preparation method thereof, belonging to the technical field of materials. The selectively passing material is provided with a channel used for passing of helium, the channel is formed by a release process of helium which is generated by neutron irradiation for the material. The preparation method of the selectively passing material comprises the steps of: mixing powdery metal with powdery <10>B elementary substance/compound; sintering the mixture to obtain a matrix; then performing neutron irradiation processing on the obtained matrix; and finally performing heating processing on the matrix which is subjected to the neutron irradiation processing to release the helium generated by the neutron irradiation to form the selectively passing material. According to the selectively passing material and the preparation method of the present invention, the problem of preparing a <238>Pu helium-passing plutonium-blocking material is solved, and the characteristic that <10>B reacts with neutron to generate helium is ingeniously utilized to form a specific channel for diffusion of helium atoms, excellent selectively passing performance is achieved, in addition, the condition of each step of the preparation process can be easily controlled, thereby avoiding the disadvantages of low yield and unstable quality of foreign technology, and the selectively passing material also can be used as a helium-passing window material for being popularized and applied to alpha decay isotopes besides the <238>Pu.