The invention provides a method for detecting impurities in ammonium paratungstate. The method comprises the following steps: mixing ammonium paratungstate with alkali; heating firstly for dissolving ammonium paratungstate to obtain an ammonium paratungstate solution, wherein the mass-volume ratio of ammonium paratungstate to alkali is 5.000g to 30ml; heating secondly, evaporating and concentrating the ammonium paratungstate solution until the volume is 45-55ml, and cooling to acquire a mother solution and crystal substances; and heating thirdly for concentrating the mother solution until the volume is 30-40ml, and carrying out ICP measurement. According to the method, cooling crystallization and evaporative crystallization are combined for completely separating ammonium paratungstate from the impurities, and thus, data are accurate when an ICP detection method is adopted for detecting the impurities, and besides, the method is simple in steps, is convenient and rapid, and has high detection efficiency.