The invention discloses a three-dimensional covalent organic framework material based on a tetrathiafulvalene unit and a synthetic method. The material is an organic crystal skeleton which is constructed by connecting two monomers, namely tetra(4-anilino)adamantane and tetra(p-benzaldehyde)tetrathiafulvalene, by virtue of an imine bond and has a three-dimensional network structure. A preparation method of the three-dimensional covalent organic framework material comprises the following steps: in an organic solvent, uniformly mixingtetra(p-benzaldehyde)tetrathiafulvalene and tetra(4-anilino) adamantane with tetrahedral configuration, then adding a catalyst acetic acid aqueous solution, heating, carrying out crystallization, washing with a solvent, heating and carrying out vacuum drying, sothat the three-dimensional covalent organic framework material COF-TTF-Ad can be obtained. The obtained COF-TTF-Ad material has large specific surface area and a regular and ordered microporous structure and shows high-capacity gas adsorption capability in a gas (such as H2 and CH4) adsorption experiment. Therefore, the COF-TTF-Ad can be taken as an excellent gas adsorption material and can be applied to gas storage.