Abstract: Using LaNi_3.7Al_0.75Mn_0.55（La-Ni-Al-Mn）hydrogen storage alloys as the matrix,a low-cost fumed silica sol coating method was used to study the anti-poisoning modification of hydrogen storage alloy.The La-Ni-Al-Mn/SiO₂ composites show good anti-poisoning performance and cycle stability.After 50 cycles,the hydrogen absorption rate of the composites remains unchanged,and the hydrogen absorption capacity reaches 1.060%.The anti-poisoning mechanism of the composite material is as follows:the amorphous SiO₂ coating layer forms a hydrogen permeation point with a short-range orderly arrangement of atoms during the heat treatment process,which effectively blocks the permeation of macromolecular gases such as O₂,N₂.Through the optimization of the heat treatment process of the composites,the optimal heat treatment process is finally obtained at 200℃ for 2 h.