The self-supporting bag with zipper can be re-closed and re-opened. Since the zipper is not closed and the sealing strength is limited, this form is not suitable for encapsulating liquids and volatile substances. According to the different sealing methods, it can be divided into four-sealing and three-sealing. Four-sided sealing means that the product packaging has a layer of normal sealing besides the zipper sealing at the factory. The normal sealing must be torn off before use. Using the zipper to realize repeated sealing and opening, this method solves the shortcoming of the low sealing strength of the zipper, which is not conducive to transportation. The three-side seal directly uses the zipper edge as the seal, and is generally used to hold lightweight products. Stand-up pouches with zippers are generally used to pack some light solids, such as candies, biscuits, jellies, etc., but self-supporting pouches with four sides can also be used to pack all kinds of food