The invention discloses a preparation method of syndiotactic 1,2-polybutadiene, and belongs to the field of the preparation of a polymer. According to the preparation method, butadiene is taken as a monomer and a catalyst consisting of the following components is adopted: a) an organic iron phosphate compound liquid; b) aluminum alkyl and/or hydrogenated aluminum alkyl; and c) an electron donor, wherein the electron donor is phosphorus-containing organic compound and/or nitrogen-containing organic compound and/or oxygen-containing organic compound, wherein the mole ratio of the component b) to the component a) is (8-40) to 1, and the mole ratio of the component c) to the component a) is (1-7) to 1. By preparing the syndiotactic 1,2-polybutadiene by virtue of the catalyst, the preparation method disclosed by the invention is low in dosage of the catalyst, and high in conversion rate and selectivity; and by changing the type of the electron donor or the dosages of various components of the catalyst, the melting point of the polymer is adjustable within the range from 110 DEG C to 190 DEG C, so that the crystallinity degree is also adjustable within a wider range.