1. The material selection of outer layer (print) In order to improve the barrier property of liquor flexible packaging bags, recommend the use of BOPET, BOPA or KPET, KPA etc as a printing surface layer, in order to improve the barrier property, prevent scent. PVDC coated material after long-term storage, the color will turn yellow, so the higher requirements of appearance quality of packaging generally less PVDC coated materials. 2. The choice of lining material (heat sealing layer) Heat sealing of plastic soft packing layer usually adopt PE film and CPP film, flexible packaging bags of liquor is usually with automatic packing machine, it is the heat sealing layer materials put forward higher requirements. First of all, the heat sealing material should have good heat sealing eligibility (heat sealing strength, low temperature heat sealing, heat sealing pollution resistance, heat sealing temperature range and intensity of hot glue, etc.); The second is after