The invention discloses a preparation method of a macromolecule piezoelectric material, and belongs to the technical field of an electric material. The preparation method comprises the steps that firstly, biogas and bamboo splits are mixed and fermented, so that fiber is activated; then, steam explosion treatment is performed, so that the bamboo fiber is subjected to fiber separation; primary degradation is performed; after freezing, ice crystals are generated inside the fiber; the ice crystals crack under the grinding pressure, so that the bamboo fiber is refined; then, the fiber and phosphoric acid are subjected to mixed ball milling to prepare cellulose whiskers; the polyhydroxy characteristics of the cellulose whiskers are used for adsorbing precipitates; through calcination, the fiber is carbonized, and magnetic ferroferric oxide is adsorbed; finally, obtained black powder and polyvinylidene fluoride particles are mixed and are subjected to ball milling; after hot pressing sheet forming, polarization treatment is performed to obtain the macromolecule piezoelectric material. The preparation method has the advantages that the strength of a material film is enhanced by the carbonized fiber; the magnetic ferroferric oxide adsorbed by the fiber can be uniformly dispersed in a thin film; the repeatability of the film is improved, so that the structure is controllable; the service life is greatly prolonged; wide market prospects are realized.