The invention relates to a rare earth ammonium tetramolybdate preparation method, comprising the step of adding ammonium molybdate solution in nitric acid to perform acid settlement and crystallization process and the method is characterized in that the method also comprises the following steps: placing the obtained ammonium molybdate crystals in the acid settlement and crystallization process ina vacuum suction filtration tank, washing with clean water, spraying nitrate water solution doped with rare earth elements on the ammonium molybdate crystals in the suction filtration tank evenly, then spin-drying, stoving, and mixing materials to obtain ammonium tetramolybdate containing rare earth nitrate. In the preparation method of the rare earth ammonium tetramolybdate, when the acid settlement and crystallization process of ammonium tetramolybdate is performed, rare earth nitrate water solution is added in the manner of spraying to obtain rare earth ammonium tetramolybdate containing 0.1-1.0% (metal molybdenum) of rare earth oxides; the method can improve the distribution uniformity of rare earth oxides in molybdenum powder and molybdenum rods in finishing process, and has high production efficiency and low cost. The rare earth oxides in molybdenum powder prepared from rare earth ammonium tetramolybdate are distributed evenly, the metallographic structure of sintered molybdenumrods is more uniform without obvious bulk grains and the molybdenum rods can meet the demand of intensive processing of molybdenum wires.