As a packaging material, aluminum foil has the greatest advantage of excellent light shielding, moisture resistance, gas resistance and taste retention. The excellent barrier of aluminum foil bag is incomparable to any kind of plastic film and paper. The disadvantage of aluminum foil bag is that it is easy to tear, wrinkle, be corroded by acids and alkalis, and is not resistant to folding and heat. Therefore, it cannot be used as a packaging material alone. Generally, it is used as the main barrier layer to composite with paper and various plastic films to make composite materials. Compared with other metals, aluminum foil bags have the advantages of light weight, rich resources, low price, easy processing, printing, etc. So far, aluminum foil bags are the only metal materials in composite packaging bags, and aluminum foil bags are widely used in barrier packaging of various products, such as essence, spices, dehydrated food; To use PTP, high temperature cooking food packaging; Electromagnetic shielding packaging, etc.