The sofa is mainly composed of three parts: frame, filling material and fabric. (1) The frame constitutes the main structure and basic shape of the sofa. The frame materials are mainly wood, steel, man-made panels, medium-density fiberboard, etc. At present, the main material is medium-density fiberboard. The frame mainly needs to meet the modeling requirements and strength requirements. (2) The filling material plays a decisive role in the comfort of the sofa. The traditional fillers are brown silk and springs. Nowadays, foamed plastics, sponges, synthetic materials with various functions are commonly used. The filler should have good elasticity, fatigue resistance and long life. The loading and comfort requirements of different parts of the sofa are different. The performance and price of fillers vary greatly. (3) The texture and color of the fabric determine the taste of the sofa. At present, the varieties of fabrics are really dazzling. With the progress of science and technology, the varieties of fabrics will become more and more abundant. The general structure of the traditional sofa (bottom-up): frame-wooden strip-spring-bottom gauze-brown cushion-sponge-inner bag-outer cover. The general structure of modern sofas (from bottom to top): frame-elastic band-bottom gauze-sponge-inner bag-coat. It can be seen that the production process of modern sofas omits the time-consuming and labor-intensive process of fixing springs and laying cushions compared with traditional sofas.