The invention discloses a preparation method of a polyoxometalate cluster-based supramolecular polymer. The method is used to solve the technical problem of a single function of the polyoxometalate cluster-based supramolecular polymer prepared by an existing method. The technical scheme is as follows: a ligand group of 2, 2', 6', 2''-tripyridine is connected to the two ends of an Anderson type polyoxometalate cluster by using an organic modification manner, a coumarin group-terminated surfactant is modified around the polyoxometalate cluster by using an electrostatic modification manner, and the obtained monomer is used to synthesize the crosslinked supramolecular polymer by the metal-ligand coordination action and coumarin photo-dimerization. The coumarin group can be reversibly dimerizedand dissociated under different wavelength lights, so that the prepared supramolecular polymer has both ionic stimulus responsiveness and photo stimulus responsiveness, and the supramolecular polymeris more functional.