From the physical point of view, have an appropriate degree of cling film oxygen permeability and permeability humidity, regulating the storage of goods around the oxygen content and water content, blocking dust in the air, food and prolong the preservation period. Therefore, the different choice of different food preservation film is necessary. Now on the market cling film can be divided into two categories are ordinary cling film, applied to the refrigerator preservation; a class of film preservation is a microwave oven, refrigerator can be used fresh, can also be used for microwave ovens. After the film preservation in a heat-resistant, non-toxic, and so far superior to ordinary cling film. Therefore, the use of consumer choice to pay particular attention, made use of.