The invention discloses a synthetic method of a covalent organic framework (COF) material. The method comprises the following steps: after mixing 1,3,5-benzenetricarboxaldehyde with 2,5-di(N,N-dimethyl)amino-1,4-benzdihydrazide uniformly in an organic solvent, reacting in the presence of a catalyst acetic acid to obtain the COF material, wherein the mole ratio of 1,3,5-benzenetricarboxaldehyde to 2,5-di(N,N-dimethyl)amino-1,4-benzdihydrazide is 1:(0.5-3). The COF material obtained by adopting the method has relatively large specific surface area and regular open framework structure with adjustable diameter, thus being beneficial for mass transfer of reactants and products in photoabsorption and catalytic processes; the material can serve as a photocatalyst and can increase the yield of the dehydrogenative coupling reaction between 2-phenyl-1,2,3,4-tetrahydroisoquinoline and nitromethane from 39% in the absence of catalysts to 89%.