Material preparation is the premise of 3D printing. However, most of the existing devices are the original plastic extruding machine. While the processing properties, rheological properties of carbon fiber composite material have great difference with ordinary plastic of 3D printing molding. The material extrusion principle, material extrusion device and process conditions were studied for the producing of carbon fiber composite material 3D printing. The theoretical and experimental analyses of the material characteristics provide the foundation for the reality of carbon fiber composite material 3D printing system.