A method for assembling and synthesizing Cu2O particle-supported porous CuBTC includes the following steps of: 1) dissolving polyvinylpyrrolidone (PVP) in ethanol solution to obtain a PVP-ethanol solution; 2) dissolving copper salt in distilled water, and mixing with trimesic acid, salicylic acid, and the PVP-ethanol solution obtained in step 1) under stirring; and 3) conducting a hydrothermal reaction on the mixed solution obtained in step 2) at 120° C. to obtain Cu2O particle-supported porous CuBTC. The new method introduces salicylic acid during the synthesis of CuBTC. The salicylic acid, as a ligand precursor, forms a porous CuBTC material through the unsaturated coordination of a ligand under the catalysis of Cu ion. The resulting porous CuBTC supported with ultrafine Cu2O nanoparticles can adsorb high-energy molecules and exhibit excellent crystallinity, porosity, and stability.