1, the inner packaging plastic should have a good barrier to water vapor and oxygen infiltration. 2, the cold resistance of plastic is better, if the packaging material cold resistance is poor, in the late transport and loading process, frozen food sharp bumps will pierce the packaging, causing leakage, accelerate food corruption. Frozen food packaging usually select high barrier, high-strength inner packaging materials, in addition through the composite or coextrusion to improve the inner packaging material cold resistance and mechanical strength. Frozen food used in the field of plastic soft packaging is mainly divided into single-layer bags, composite soft plastic bags, multi-layer coextrusion soft plastic bags, edible packaging film. Flexible packaging has a considerable amount of lower cost materials to choose from, including polyethylene terephthalate (PET) or polyester (APAT). These materials can be flexibly designed into a variety of three-dimensional shapes and sizes, so this type of soft package can be changed at any time according to the volume of dough, and is very flexible to use.