Provided is a method for detecting impurities in ammonium hydroxide. The method for detecting impurities in ammonium hydroxide includes preparing a potassium permanganate solution, preparing ammonium hydroxide, and adding the potassium permanganate solution several times to the ammonium hydroxide so as to detect impurities in the ammonium hydroxide. Potassium permanganate contained in the potassium permanganate solution is added for each time in the range of 0.0001 mol to 0.01 mol per 1 g of ammonia contained in the ammonium hydroxide.