The global market of 3D printing materials accounted for US$600 mln in 2014 and is expected to reach US$2.5 bln by 2020 at a CAGR 30%. In these materials, thermoplastic polymer materials stable account for more than 40%. 3D printing will be gradually introduced into industry, customer-made products and other applications, so high-strength and high-performance material will be the major evolution in the future. Although thermoplastics reinforced by glass fiber have well performance, but that can not be used in 3D printing system. Because the length of glass fiber is greater than nozzle aperture, so glass fiber will block the nozzle when we printed it. Therefore materials used in 3D printing are still pristine thermoplastics, the performance of these materials are poor after printing. Self-assembly fiber reinforce thermoplastic not only can enhance the properties of the materials but also can prevent the problem of nozzle blocked. This technology can allow the applications of 3D printing expand to high-performance product. Key word：Self-assembly fiber、Thermoplastic composites