The invention provides a high efficient external control type antistaling agent, which, according to the percentage of the quality, is composed as the following; 30 to 50 per cent silicon dioxide, 49.995 to 68 per cent edible alcohol and 0.005 to 2 per cent allyl isothiocyanate. The antistaling agent is obtained by using the following methods: mixing the edible alcohol and the allyl isothiocyanate according to the quality percentage and then mixing with the silicon dioxide; then loading the mixture into a moisture permeability packaging film after stirring evenly under normal temperature for sealing. The invention can be used for storing food, medicinal materials, reagent, tobacco and leather. When it is used for storing food, packing the invention into packet, scraps with the moisture permeability packaging film and then placing them into the package of food to make the antistaling agent being released slowly in gas mode and being volatilized into the internal gaps, thus forming a gas phase protective layer with certain concentration around the food to be preserved, so as to effectively restrain, kill many kinds of leaf mold and bacterium as well as other spoilage organisms; besides, the invention increases the permeation pressure in the package and lowers the water activity of the food, so as to preserve the food.