Microporous bag is a kind of bag with special breathability. The key of microporous bag is that its microporous structure can allow gas molecules to pass through while blocking liquid and solid particles. For example, it can make the products in the packaging bag such as fresh vegetables, fruits, etc., can "breathe", release the generated carbon dioxide, while absorbing external oxygen, thus extending the freshness of the product. Microporous bags are mainly used in the field of food packaging, especially fresh food and processed foods that need to breathe. In addition, it is also used in some non-food product packaging with high breathability requirements, such as flower packaging, which can effectively maintain the freshness and quality of products.