The invention provides a method for treating printing and dyeing wastewater by using amorphous powder. The method includes the following steps: under the condition of stirring, adjusting the initial pH value of the wastewater to 1.0-5.0 by using sulfuric acid, adding hydrogen peroxide and a catalyst, adjusting the reaction temperature of the wastewater to be 30-75 DEG C, and maintaining the reaction at constant temperature for 5-15 min, wherein the catalyst is the amorphous powder. The method uses the amorphous powder as the catalyst, by controlling parameters such as the reaction temperature,the addition amount of the catalyst, the concentration of the hydrogen peroxide and the initial pH value of the solution, the purpose of efficient degradation of the phenol-containing printing and dyeing wastewater can be achieved, and the degradation efficiency of phenol within a few minutes can reach 99%; and the method is simple and efficient, has mild reaction conditions, simple and convenient operation and low operating costs, and is convenient for industrial large-scale application.