Consisting of inner-layer film extruder, outer-layer film extruder and combination die, it adopts LDPE, HEDPE or LLDPE as the raw materials for inner-layer film extrusion and EVA for outer-layer film extrusion. The film is extruded through the double-channel combination die and then is blown and rewound. The final product can be used as the liner inserted into the fabric and then made into laminated bags by reverse lamination machine.