The mixed plastic raw materials are put into the extruder, heated to reach a molten state, and under the action of pressure, extruded through a specific die to form a tubular plastic film. The film blowing machine blows the molten plastic into a film bubble, cools it under the action of the traction air ring, stabilizes the size and shape of the film, and makes a plastic film that meets the requirements of width, thickness and embossing, which is the direct raw material for making plastic bags.