The invention discloses a durable chemical ice bag and a preparation method thereof. The durable chemical ice bag is prepared from the following components in part by weight: 60 to 70 parts of ammonium nitrate, 60 to 70 parts of sodium carbonate decahydrate, 20 to 30 parts of aluminum potassium sulfate dodecahydrate, 1 to 4 parts of polyvinyl alcohol, 3 to 7 parts of ethanol and 10 to 20 parts of sodium chloride. The preparation method for the durable chemical ice bag comprises the following steps of weighing the components according to the weight parts; adding the weighed polyvinyl alcohol into the aluminum potassium sulfate dodecahydrate for stirring; heating a mixture to 90 to 100DEG C; when a solution becomes transparent, stopping heating, and naturally cooling the solution to room temperature to obtain a solution A; sequentially adding the ammonium nitrate, the sodium carbonate decahydrate and the ethanol into the solution A by stirring, and uniformly stirring a mixture to obtain a solution B; adding the sodium chloride into the solution B; when the solution is uniformly stirred and becomes transparent, packaging with bags to obtain the durable chemical ice bag. The durable chemical ice bag disclosed by the invention is long in refrigeration time.