The invention discloses a sterilization addition agent for substitute cultivation of edible fungi and an application method of the agent. The sterilization addition agent is composed of sodium dichloroisocyanurate, calcium oxide, zeolite powder and other components. The method comprises the steps that in stirring of substitute cultivation of the edible fungi, a certain amount of sterilization addition agent is evenly mixed with wheat bran and gypsum at first, then the mixture is evenly stirred with other cultivation materials, finally, water is added to the mixture, the mixture is evenly stirred, adjustment is conducted until the mixture has proper water content, and bagging is conducted. When sterilization is conducted by using the sterilization addition agent, the temperature of materials of a fungus bag only needs to be increased to 95 DEG C or above for 5 hours, then fire extinction and braising are conducted, and after the fungus bag is naturally cooled to 50 DEG C or below, sterilization is ended. By means of the method, the sterilization time can be saved by 50%, the fuel is saved by 60%, the energy is saved, the environment is protected, the efficiency is high, and the yield of the cultivated edible fungi is high.