The invention discloses a method for treating waste by adopting a microwave plasma torch. The method comprises the following steps: pretreatment of waste, namely preparing solid waste, liquid waste and gaseous waste, and crushing the solid waste by virtue of a crushing device; and pyrolysis, namely generating a plasma torch by carrying out ionization on gas by utilizing a microwave plasma generation device, and carrying out the pyrolysis on the pre-treated waste by virtue of the plasma torch, wherein organic matters in the waste are pyrolyzed into micromolecular substances such as C, H2, CO, and CH4, and inorganic matters in the waste are molten at the high temperature to form a matter in a glass state. According to the method, the waste is pyrolyzed by virtue of the plasma torch generated by the microwave plasma generation device, the waste is pyrolyzed into the micromolecular substances, such as carbon oxide, carbon powder, methane, and hydrogen, and the matter in the glass state, no harmful matter is generated in the treatment process, the secondary pollution for the environment is avoided, the treatment procedure is simple, and the efficiency is relatively high.