The invention relates to an extrusion device for thin films. The extrusion device for the thin films comprises a cylinder body and a screw assembly; the screw assembly is arranged in the cylinder body; one end of the cylinder body is provided with a hopper for feeding raw materials of the thin films into the cylinder body; a discharge port is formed in the other end of the cylinder body; the screw assembly comprises two parallel screws; a plurality of spiral parts of different specifications are arranged on each screw; the rotating directions of the corresponding spiral parts on the two screws are the same, and the corresponding spiral parts on the two screws mesh with each other; a driving device used for driving the two screws to rotate relatively in an opposite direction is arranged on the cylinder body; the lower end of the discharge port is connected with an extrusion mold head device; and a composite device used for cooling the extruded thin films is correspondingly arranged at the lower end of the extrusion mold head device. The double-screw extruder adopts a double-screw rotary extrusion mode, and therefore the friction heat generated in the extrusion process of the raw materials is small; the meshing and shearing effect of the raw materials in the cylinder body by the screws is stable and uniform; the raw materials are mixed well, and the plastic quality is relatively good; and the conveying capability of the materials is improved.